It is useful for the walls of capillaries to consist of a single layer of thin, flattened cells in order to easily diffuse oxygen and nutrients easily from the blood and into the capillaries. Not only that, but this also makes it more efficient for carbon dioxide and other waste molecules to diffuse from the capillaries and into the blood. If capillaries were thicker than a cell, then it would be more difficult for materials to diffuse through the thick layer of cells.
Contractile vacuole is an organelle will be found in chlorella but not the paramecium.
The lowest metazoans, such as sponges and hydras, and freshwater protozoa have regulating organelles called contractile vacuoles that gather extra fluid from the protoplasm and occasionally release it into the surrounding media. Wastes containing nitrogen may also be excreted.
The contractile vacuole (CV) complex is an osmoregulatory organelle found in free-living amoebae and protozoa that regulates intracellular water balance by storing and excreting excess water, enabling cells to survive under hypotonic stress, like that found in pond water.
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Answer:
motor cortex association
Explanation:
The motor cortex is one of the parts of the telencephalon, which in turn is part of the brain. Its main function is to favor movement. Then through it we generate, maintain and finalize the movements.
Thanks to the motor cortex we can make voluntary movements consciously. This brain region is located in the frontal lobe, just in front of Rolando's fissure and somatosensory region.
If the part of the brain where the motor cortex is located is injured, movement of some part of the body may be lost or limited. For this reason, if Marta lost her arm movements after a brain injury caused by an accident, we can conclude that this injury injured the motor cortex.
Answer:
a. The purple allele is lethal in the homozygous state
Explanation:
You cross a purple parrot with a true breeding (homozygous) white parrot and you get 1/2 purple parrots and 1/2 white parrots. This result can only happen if the purple parrot is heterozygous and the white parrot is homozygous recessive (if any of the parents had been homozygous dominant, 100% of the offspring would have had the dominant phenotype).
Then: Pp (purple) X pp (white) ---> 1/2 Pp, 1/2 pp
When you cross two purple parrots you get 1/3 white parrots and 2/3 purple parrots. The 2:1 phenotypic ratio is typical of a lethal allele in the homozygous state.
In a cross of two purple parrots: Pp
X Pp, one would expect the genotypic ratios 1 PP : 2 Pp : 1pp and the phenotypic ratios 3 Purple : 1 white.
But the PP genotype is lethal, so those individuals die and the only purple parrots we see are the heterozygous ones.