Answer:
Theory of Measurements:
Leaf photosynthetic rate is measured by enclosing a leaf in a closed, transparent chamber and measuring the decrease in carbon dioxide concentration as a function of time.
The presence of which type of intercellular connections between endothelial cells of brain capillaries results in the blood–brain barrier?.
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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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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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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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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Given the number of blood vessels in the retina, why do you suppose that you are not able to see them normally
Answer:
You can't see the blood vessels themselves because vision depends on a process that makes it impossible to see things that are stationary with respect to the retina. Light receptors in the retina respond only to changes in light reaching them, not to a steady image.
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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:
True or false: Tonic contraction of smooth muscle in blood vessels is important in maintaining blood pressure.
When testing the effect of light on flowering patterns of plants, temperature would be considered a?
A.independent variable
B. dependent variable
C. constant
Answer: Independent Variable
Explanation: Already explained this one in another post.
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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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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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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Which of the following help to break down proteins?
Answer:
b. Pepsin and trysin
Explanation: is correct
Three types of macromolecules are mentioned in the video that are digested and ABSORBED in the small intestine. What do they all get absorbed into first?
Lacteals
Epithelial cells
Capillaries
Given what we know about the biology of the small intestine, we can confirm that the macromolecules are being absorbed into the "Epithelial cells".
The small intestine is in charge of absorbing the nutrients, which we require in order to survive and perform even the most basic metabolic processes, from the food that we ingest. In order to be able to perform this function, the cells in question have specialized epithelium which consists of Microvilli.
Microvilli can be thought of as membrane protrusions that serve to expand the surface area of the epithelial cells. This allows the cells to have a greater area through which to absorb nutrients such as the macromolecules mentioned.
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When is it important to drink water?
Answer:
d. All of the above
Explanation: correct
Answer:
? why did you post this
Explanation:
