what modern day scientist use to learn the Ordovician Period
Rocks from the Ordovician Period contain evidence that plants began colonizing dry land at this time. Most experts agree that the ancestors of land plants first evolved in a marine environment, then moved into a freshwater environment and finally onto land.
Ordovician Period, in geologic time, the second period of the Paleozoic Era. It began 485.4 million years ago, following the Cambrian Period, and ended 443.8 million years ago, when the Silurian Period began. Ordovician rocks have the distinction of occurring at the highest elevation on Earth—the top of Mount Everest.
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Which of the following help to break down proteins?
Answer:
b. Pepsin and trysin
Explanation: is correct
How did the new island in the Pacific Ocean near the Vava'u Islands form? See below
for a picture of the new islands and for the location on earth.
Answer:
They were created from the subduction of the western-moving Pacific plate under the Australia-India plate at the Tonga Trench. The Tongan Islands sit on the Australia-India plate just west of the Tonga Trench. These volcanoes are formed when materials in the descending Pacific plate heat and rise to the surface.
Explanation:
The new island in the Pacific Ocean near the Vava'u Islands forms as divergent plates allow magma to come to the surface at this location. The correct option is a.
What are Vava'u Islands?Vava's island is a group of islands that contain one large island and 40 smaller islands. They are present in the Tonga region.
They were formed as a result of the subduction of the Australia-India plate beneath the western-moving Pacific plate at the Tonga Trench.
West of the Tonga Trench on the Australia-India plate is the Tongan Islands. When elements in the descending Pacific plate heat up and rise to the surface, volcanoes like this are created.
Therefore, the correct option is a. divergent plates allow magma to come to the surface at this location.
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Which of the following statements correctly describes genes?
Answer:
Genes are made of DNA and are carried on chromosomes
Explanation:
if mammalian cells receive a go-ahead signal at the g1 checkpoint, they will:
If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will complete the cell cycle and divide normally.
What is the Cell Cycle?The cell cycle may be defined as the entire sequence of events happening from the end of one nuclear division to the beginning of the next nuclear division.
There are three major checkpoints in the cell cycle. One at the end of the G1 phase, the second at the end of the G2 phase, and while third is during the M phase.
Therefore, if mammalian cells receive a go-ahead signal at the G1 checkpoint, they will complete the cell cycle and divide normally.
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the three steps that are required for dna replication are
Replication occurs in three major steps: the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment.
The three steps that are required for DNA replication are initiation, elongation and termination.
What is DNA replication ?The process in which DNA of a cell under go duplication to produce two copies during S-phase of cell cycle called as DNA replication.
It involves 3 steps such as initiation step where the origin of replication of DNA molecule undergo unwinding into two DNA strands.
An incomplete unzipping by forming replication fork is created is catalyzed by the helicase enzyme.
Secondly in elongation step the DNA polymerase enzymes make the complementary sequence against each parent template strand.
It is an unidirectional, one strand which is synthesized in a continuous manner called leading strand, the strand which is synthesized in a discontinuous manner called lagging strand with Okazaki fragments.
Termination occurs in the last step, when the parent molecule has been completely replicated.
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why not test for pathogens like salmonella directly rather than use an indicator organism such as a coliform?
Indicator organisms are organisms that are utilized to detect the presence of another organisms that cannot be easily identified.
We do not test for pathogens like salmonella directly but use an indicator organism like coliform because these pathogens are not easily isolated and they are much harder to identify.
Pathogens like salmonella are not tested for directly because they are much lower in numbers when found in wastes or waterbodies and to identify them directly is expensive.
Also testing directly for these micro-organisms is very expensive and non-viable. So it is better to use indicator organisms to detect their presence.
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Where does energy go in respiration
Answer:
Summary. Through the process of cellular respiration, the energy in food is converted into energy that can be used by the body's cells. During cellular respiration, glucose and oxygen are converted into carbon dioxide and water, and the energy is transferred to ATP.
please help i will give brainliest
Answer:
Mark Brainliest
Explanation:
Trap NestSaltStarter MashInternetPneumoniaPeiits GoatsChicken CoopPlankTonsFertilizerWhat does the type of animals and plants brought to the New World demonstrate about the needs of Pre-Columbian civilizations
Answer:
The answer would be D because Pre-Columbian civilizations didn't have any domesticated animals such as cows, chickens, and horses. This fact limited the accessibility to meat for the Pre-Columbian civilizations.Explanation:
What is a fishing bed
distinguish between uric acid, urea and ammonia
Answer:
Explanation:
Ammonia is associated with aquatic animals; urea is associated with most terrestrial and semiterrestrial vertebrates, but rarely land invertebrates (Campbell et al., 1972); and uric acid is the major product of terrestrial invertebrates, birds and reptiles (Prosser & Brown, 1961).
Which two atoms form an ionic bond?
A.sodium and bromine
B. two sodium atoms
C. two oxygen atoms
D fluorine and chlorine
Answer:
sodium and bromine
Explanation:
The one valence electron from sodium would be transferred to the bromine atom so they can both have an octet.
Which two atoms form an ionic bond?
Answer : A
Explanation : Ionic bond is a type of chemical bond and binds the chemical molecules together. Ionic bond is formed by the transfer of electrons from an electropositive element ( metal) to the electronegative element (non metal).
Sodium is an electropositive element and contains one positive charge. Bromine is an electronegative element with a single negative charge over it. Sodium gives the electron to bromine and results in the formation of ionic bond.
Thus, the correct answer is option (C).
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The following list of events happens during meiosis:
Prophase I: Crossing over between homologous chromosomes occurs.
Metaphase I: Tetrads line up at the metaphase plate.
Anaphase I: Tetrads are separated.
Telophase I: Nuclear envelopes reform around the separated chromosomes.
Prophase II: Chromosomes condense.
Metaphase II: Chromosomes line up at metaphase plate.
Anaphase II: Sister chromatids separate into daughter chromosomes.
Telophase II: Nuclear envelopes reform around the daughter chromosomes.
Identify the answer choice that correctly lists the events from above that lead to new genetic combinations in the gametes.
(1 point)
1 and 2
1, 2, and 5
5 and 6
5, 6, and 7
Meiosis is a form of cell division that occurs in the sex chromosomes. This form of division ensures genetic diversity and also allow for the chromosome set to be halved.
The events from above that lead to new genetic combinations in the gametes include:
Prophase I: Crossing over between homologous chromosomes occurs.
Metaphase I: Tetrads line up at the metaphase plate
(1 and 2) option a.
During meiosis, possibilities of new genetic combinations occurs which allows for variations to exist between the offspring and parents. These ensures that offspring are not entirely identical to the parents and also allow for survival and other benefits.Learn more about genetic combinations: https://brainly.com/question/8418041
where would the majority of the dna be located within a eukaryotic cell?
Answer:
cell nucleus
In eukaryotic cells, most DNA is located in the cell nucleus (though some DNA is also contained in other organelles, such as in the mitochondria and the chloroplast in plants). Nuclear DNA is organized into linear molecules called chromosomes.
Explanation:
Which of the following sentences state a significant conclusion that Gregor Mendel drew from his experiments with pea plants? Traits are inherited in discrete units and are not the result of "blending." Genes are composed of DNA. Recessive genes occur more frequently in the F1 generation than do dominant ones. There is considerable genetic variation in garden peas.
Mendel concluded that the alternative forms of each trait are coded by discrete factors, which were called alleles that combine in pairs to express the trait. Traits are inherited in discrete units and are not the result of "blending."
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After making many crosses that involved different traits -such as plant height, or flower colors-, Mendel observed that, per trait, the F1 only expressed one of the alternative forms, while de other one disappeared.
Mendel named dominant the expressed variant.
Mendel then let these new plants auto pollinate and observed the results in the second generation, F2.
He saw that the variants that had previously disappeared among the F1, reappeared again. Both alternatives for each trait were present in the F2.
Mendel named recessive the second alternative variant.
Mendel explained his results by arguing that discrete factors were responsible for these phenotypes.
These factors should have been present in the F1 in pairs. One of them came from one parental plant, and the other factor came from the other plant. These factors separated again during sex cells formation, producing two types of gametes, each with only one factor.Mendel conclusion about his experiments was that per trait -flower color of plant length-, each plant had a pair of factors -which he named alleles-, and that each factor coded for one of the alternative forms of the traits -white or purple, tall or short-.
He thought that alleles separate -segregate- during the process of gamete formation.
The First Mendel's Law is the first conclusion he took about his experiments and is known as the segregation principle.
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Explain how pollution from one location
can affect the environment far away from the
source of the pollution
Answer:
Air quality is affected by natural processes. Wind can move pollutants from their source to far-away locations. It can still spread and harm living creatures and destroy their environments.
Explanation:
Air quality is affected by natural processes where wind can carry pollutants to places far away from their source which can still spread and harm living beings and destroy their environments.
What is Pollution?Pollution is defined as the introduction of harmful materials into the environment where the harmful materials are called pollutants. Pollutants can be natural, such as volcanic ash which can also be created by human activity, such as waste or runoff produced by factories. Pollutants harm the quality of air, water and land.
Many things produce pollution such as cars spewing pollutants from their exhaust pipes. Burning coal to generate electricity pollutes the air. Industries and homes generate waste and sewage that can pollute land and water. Pesticides which is chemical poisons used to kill weeds and insects which is seep into waterways and harm wildlife.
Thus, air quality is affected by natural processes where wind can carry pollutants to places far away from their source which can still spread and harm living beings and destroy their environments.
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True or false: Tonic contraction of smooth muscle in blood vessels is important in maintaining blood pressure.
Which plate is the Eurasian plate?
A. D
B. C
C. B
D. A
Chitin is all of the following EXCEPT ________. Found in insect and crustacean shells Composed of N-acetylglucosamine subunits Composed of linear fibrils like cellulose Found in plant cell walls
Answer:
Found in plant cell walls
Chitin is all of the following except it is found in the plant cell wall. So, the correct option is D.
What do you mean by Cell wall?It is the outermost layer of a cell that can be tough, flexible, and sometimes rigid. Its function is to provide structural support and protection to the complete cell.
The Cell-wall of fungi is made up of chitin. It is composed of N-acetylglucosamine subunits. It is also composed of linear fibrils like cellulose. Mostly, found in insect and crustacean shells.
Therefore, Chitin is all of the following except it is found in the plant cell wall.
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objects are brought into focus on the retina by changes in the curvature and thickness of the
Objects are brought into focus on the retina by changes in the curvature and thickness of the lens.
What is eye lens?The lens basically directs light rays onto the retina. The lens is clear and replaceable if necessary. As we age, our lenses deteriorate, necessitating the use of reading glasses.
The lens is normally clear and is located behind the iris. The pupil directs light to the lens.
Small muscles attached to the lens can cause the lens to change shape, allowing the eyes to focus on objects that are close or far away.
Light bends (refracts) and focuses on the retina at the back of the eye as it passes through the lens.
The lens's thickness and curvature can be adjusted to focus on objects at various distances and ensure that the image is as clear as possible (this process is known as accommodation).
Thus, eye lens helps to focus the object.
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If two 4-Newton forces act on an object in the same direction, what is the net force on the object?
Answer:
8 Newton net force
Explanation:
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