The switch from mitosis to meiosis in spermatogenesis is regulated by _____ levels of _______ and this is induced by _________. Fill in the blanks. Group of answer choices low, glial cell derived neurotrophic factor (GDNF), luteinizing hormone (LH) high, glial cell derived neurotrophic factor (GDNF), luteinizing hormone (LH) low, testosterone, follicle stimulating hormone (FSH) low, glial cell derived neurotrophic factor (GDNF), follicle stimulating hormone (FSH)

Answer:

Motor Neurons

Answer:

The neurons that carry messages to the muscles are called motor neurons.

Answer:

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Answer:

recessive

Explanation:

A lethal allele is a gene variant associated with a mutation in an essential gene, which has the potential to cause the death of an individual. In general, lethal genes are recessive because these alleles do not cause death in heterozygous individuals, which have one copy of the normal allele and one copy of the allele for the lethal disease/disorder. In recessive lethal diseases, heterozygous individuals are carriers of the recessive lethal allele and can eventually pass the 'defective' allele on to offspring even though they are unaffected; whereas dominant lethal diseases are caused by dominant lethal alleles, which only need to be present in one copy to be fatal. In consequence, the frequency of recessive lethal alleles is generally higher than dominant lethal alleles because they can be masked in carrier individuals. Some examples of human diseases caused by recessive lethal alleles include, among others, Tay-Sachs disease, sickle-cell anemia, and cystic fibrosis.

The frequency of a lethal allele in a population is greatest when it is: C. recessive.

A lethal allele can be defined as an allele that is responsible for the death of a living organism, especially by preventing its development. Thus, a lethal allele causes a complete mortality in the living organism carrying it, in a hom-ozygous condition.

Basically, a lethal allele is recessive in nature because it is expressed in the phenotype of an organism. Some examples of diseases caused by lethal alleles in humans are:

In conclusion, a lethal allele that is recessive has the greatest frequency in a population.

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Answer:

b. are energy-yielding (under standard state conditions).

d. yield ATP.

Explanation:

The reactions of glycolysis produces the ATP molecules from the breakdown of glucose molecule. Glycolysis produces 2 molecules of ATP, 2 molecules of NADH, and 2 molecules of pyruvate: Glycolysis breakdown glucose with the help of oxygen produces energy in the form of ATP, NADH, and pyruvate so e can conclude that glycolysis are energy-yielding process for the cell.

DNA is replicated in a semi-conservative manner (option C). Details about DNA replication can be found below.

DNA replication is the process by which a new strand of DNA is synthesized prior to the process of cellular division.

DNA replication occurs in the S-phase of the interphase stage, before the nucleus of the cell divides.

DNA is replicated in a semi-conservative manner in such a way that one strand serves as a template for the other.

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Answer:

option A they have developed from the same organism

Explanation:

Organs of animals (belonging to different species) which have similar structure but different functions are homologous organs. Such organs have evolved from the same ancestors , however their function are different.  

For example – wings of bats, limb of human etc.  

Here in this case  also the bone structures of human, cow, and horse are same but their functions are different, thus they are homologous organs and hence they have evolved from same ancestors.  

The correct answer is option A

Answer:

"They have developed from the same organism."

Answer:

After a fire

Explanation:

Primary succession is one of the two types of ecological succession in which a barren area of land (with no soil) is colonized by organisms called PIONEER SPECIES for the very first time.

Primary succession is characterized by a BARREN area that had no form of previous growth or colonization. These barren area can include a retreating glacier, an emerging islands or the formation of new lakes.

Note that, the succession that occurs AFTER A FIRE or any form of environmental disturbance is SECONDARY SUCCESSION.

Answer:

5+x/8=42

Explanation:

This is your answer to the equation.

If you want to solve it, then subtract 5 from both sides to get x/8=37. Then multiply both sides by 8 to get x=296

Hope this helps!! :)

Answer: True.

Explanation:

A population is defined as the set of individuals that inhabit a given geographic area. A population has a certain allele frequency, which is the measure of the relative proportion of alleles in a given population, expressed as a percentage or unit. It is estimate using the number of times the allele is found in a locus and dividing it by the total number of alleles. While the genotypic frequency refers to the number of times that each of the genotypes generated by the two-by-two combinations of the alleles involved in the locus under study appears in relation to the total number of genotypes (which will be equal to the total number of individuals included in the study).

The population can be increased or decreased according to the birth and death rates. Generally, unless specific alterations occur, such as the spread of a disease, immigration, emigration, natural disasters, and others, the size of the population will remain constant. This means that the birth rate is quite similar to the death rate. And the larger the population, the more difficult it is to disturb this balance between births and deaths. So if small fluctuations in survival or reproduction occur between individuals, it is unlikely that this will affect the frequency of alleles and/or genotypes.   This is explained using the Hardy-Weinberg principle states that the genetic composition of a population remains in equilibrium as long as no mutation occurs, and nor natural selection nor any other factor acts. After a generation of random mating, the frequencies of the genotypes of a locus are fixed at an equilibrium value. Then, the genetic variation in a population will remain constant from one generation to the next in the absence of extreme disturbing factors such as those mentioned above (diseases, natural disasters, and others).

Note that for this principle to be fulfilled, the population must be diploid (have two alleles of each gene), must reproduce sexually in a random manner, and must be large enough to minimize the effect of genetic drift (random fluctuations in allele frequencies from one generation to the next, due to random events that can cause certain traits to become dominant or disappear from a population).

Answer:

Molecules, cells, tissue, organ, organ system, organism, population, community, ecosystem, and biosphere are in the correct order of the organization's levels.

Explanation:

Molecule: Atoms, the smallest unit of chemical elements are built up of molecules. You can find it in any matter, whether it lives or not. The most fundamental structures of biological creatures are molecules. Biochemistry and molecular biology are two biological fields focused on this level.

Cell: A cell is the basic unit of life. Two types of cells exist plant cells with a stiff cell wall consisting of cellulose molecules and animal cells with a flexible cell membrane. Cell biologists examine problems like metabolism and other structure and functional questions within and between cells.

Tissue: Tissue consists of cells working together to accomplish a goal. Some tissues include muscle, connective tissue, and neural tissue. Examples of biologists working at this level are histologists.

Organ: An organ is a tissue system that works at bigger scales together to perform specified work in the body of an animal. Brain, heart, and lungs are examples of organs. Anatomy is an example of a specialty in biology which concerns this level.

Organ system: An organ system is a group of bodies that work together to fulfill certain activities of the body. Air systems are used to inhale oxygen and release carbon dioxide in animals, for example, by the lungs, respiratory tract, and muscles. The function of the corpus when working jointly is studied by physiologists. Although physiologists can work at any level, they commonly address queries about organ systems.

Organism: An organism is an autonomous and recognized person. The organisms might be single-cell or multi-cell organisms consisting of organisms and organ systems, as well as bacteria, amiable, or creatures. An example of a multi-cellular organism is a human being.

Answer:

He could determine whether the hypothesis is based on repeated experiments.

Explanation:

A theory is a hypothesis that has been proven correct by many expirements.

Francis could design and perform a new controlled experiment to test the hypothesis to determine whether it is a theory. Therefore, the correct statement is option D.

A hypothesis is a scientific explanation for a phenomenon that is based on prior observation. However, a theory is a well-supported and widely accepted explanation for a natural phenomenon that has been tested and based on scientific fact.

A hypothesis has the potential to become a theory if tested through carefully designed and controlled experiments by collecting data needed for the experiment.

If the results of an experiment conducted by Francis are consistent with the hypothesis, the information can be used to develop a theory that can be used to explain a broader range of phenomena. However, if the results are not by the hypothesis, Francis cannot consider the hypothesis as a theory that must be supported by evidence.

Therefore, Francis needs to design and perform a new controlled experiment to test the hypothesis to determine whether it is a theory.

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Answer:

hair color is determined by genetics

Explanation:

Answer:

False

Explanation:

The climbers doesn't often bear big fruits. It gives small fruits and berries like Grapes, Kiwi, etc. Hence, your statement is incorrect (false).

The structure that allows lycophytes to grow bigger than mosses and liverworts is xylem and phloem which is option B

Lycophytes are spore bearing vascular plants. Being a vascular plant, they possess vessels ( vascular tissues) which include:

The possession of the vessels makes the lycophytes appear bigger.

Mosses and liverworts belongs to the plant phylum Bryophyta. They do not have any vascular tissues that can be used to conduct water and food. This restricts their size.

Therefore, the structure that allows lycophytes to grow bigger than mosses and liverworts is xylem and phloem

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Answer:

xylem and phloem

Explanation:

Lycophytes have specialized tissue that transports nutrients and provides structural support.

Answer:

an entrepreneur or innovater

Answer:

The alveoli are the sites of gas exchange; they are located at the terminal regions of the lung and are attached to the respiratory bronchioles. The acinus is the structure in the lung where gas exchange occurs. The sac-like structure of the alveoli increases their surface area.

Answer:

The question is incomplete, the complete question is as follow:

Thymine in DNA occurs as the result of thymidylate synthase creating _______, which then undergoes _______ to _______, then to _______, and incorporated into D N A by _______. Thymine in tRNA arises ________, by an S-adenosylmethionine-dependent _______ of a ______ residue in RNA.

Answer:

Thymine in DNA occurs as the result of thymidylate synthase creating dTMP, which then undergoes phosphorylation to dTDP, then to dTTP, and incorporated into DNA by DNA polymerase. Thymine in tRNA arises posttranslationally, by an S-adenosylmethionine-dependent methylation of a UMP residue in RNA.

Explanation:

Thymidylate synthase is a key enzyme that catalyzes the synthesis of 2′-deoxythymidine-5′-monophosphate (dTMP) from 2′-deoxyuridine-5′-monophosphate (dUMP). This enzyme catalyzes the addition of a phosphate group (phosphorylation) of dTMP in order to form thymidine 5'-diphosphate (dTDP). Once synthesized, dTMP can be metabolized to deoxythymidine triphosphate (dTTP), which is a precursor for DNA biosynthesis. On the other hand, transfer ribonucleic acid (tRNA) is methylated after the molecule is synthesized. The transfer of the methyl group is catalyzed by an S-adenosylmethionine–dependent methyltransferase that catalyzes the methylation of uridine monophosphate (UMP) using SAM (S-adenosylmethionine) as the methyl donor.

Answer: All of the choices are correct.

Explanation:

Meiosis is a type of cell division of the nucleus that occurs in cells that will give rise to gametes (egg or sperm). These are haploid cells (n), that is, they possess only one chromosome of each of the pairs (23 in total). Through meiosis from a diploid cell (2n), four haploid cells are obtained, thanks to two successive divisions called meiosis I and meiosis II.  Both comprise prophase, metaphase,  anaphase and telophase.

Homologous chromosomes are a pair composed of a paternal and a maternal chromosome. They have the same DNA sequence arrangement from one end to the other, but different alleles. These chromosome copies have the same genes at the same loci where they contribute tips along each chromosome that facilitate a pair of chromosomes to align correctly with each other before they separate during meiosis. Sister chromatids are those that make up a chromosome after duplication of the genetic material.  

The homologous chromosomes of maternal and paternal origin, mate and this process is called "synapsis" and form what is known as a tetrad or bivalent chromosome, giving the impression that it is a chromosome with four chromatids. In these tetrads, junctions called chiasmata are formed, areas in which both homologues exchange genetic material or genes, a process known as crossing-over. The chiasmata allow the chromosomes to be held together until their separation in anaphase l. So, genetic recombination is the process by which a segment of genetic material from a maternal chromosome is cut and then joined to a paternal chromosome (or vice versa) during prophase I of meiosis. So it happens between non-sister chromatids of a paternal and a maternal chromosome.

After crossing over, the homologous chromosomes are arranged randomly at the cell's  the equator of the cell at random (methaphase), facing each other, still united in the areas where crossing over occurred. Each chromosome is associated with a meiotic spindle fiber of the meiotic spindle and they are pulled along the meiotic spindle and driven toward the respective poles (anaphase). The chromosomes are now arranged at the poles and the reorganization of the nuclear envelope and the nucleolus begins. Finally, cytokinesis occurs and the rearrangement of cellular components and reorganization of the cytoskeleton. As a result of meiosis I,  2 haploid cells are obtained and then meiosis II occurs, where the sister chromatids are separated, generating two more cells (a total of 4).

Genetic variability is generated because the gametes produced during meiosis will not inherit the same chromosomes as the mother cell, but due to crossing over, the inherited chromosomes will be genetically different.

Answer:

Produce sperms.

Explanation:

This occurs in three stages; proliferation and spermatogia differentiation, meiosis, spermeogenesis.

Answer:

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Explanation:

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Answer:

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A solution that has a pH of 6.8

it is acidic as it has got ph value less than 7....But as it has got ph value near to 7 it is weak acidic..

Answer:

Explanation:

Chlorophyll, the primary pigment used in photosynthesis, reflects green light and absorbs red and blue light most strongly.

In plants, photosynthesis takes place in chloroplasts, which contain the chlorophyll.

Answer:

B) Chlorophyll

Explanation:

The chloroplasts, which contain the green pigment chlorophyll, are where photosynthesis takes place. Chlorophyll is the pigment that gives plants their distinctive color. It works by collecting the energy in the sunlight that strikes the plant. Because grass requires photosnthesis to create glucose, which is required for growth inside the grass, photosynthesis is critical to life on Earth. As a result, creatures that eat the grass get energy, and so on. As a result, photosynthesis is the mechanism through which energy is introduced into an environment.

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Answer: It's most likely Gamma Rays.

Explanation:

Answer:

Abiotic simply means a non-living thing.

Therefore, my understanding of the characteristics of life are those things that show that something is living.

Things like:

Movement

Respiration

Nutrition

Irritability

Growth

Excretion

Reproduction

Death.

Answer:

The double helix can be found almost everywhere in DNA. AGTC is found in lions, humans, and fish. The double helix is the most stable structure for maintaining genomic integrity in AGTC. The gene structures (that is, sequence) differ, as do promoters and other elements, but the DNA structure remains the same.

Answer: