Answer:
<em>The kidneys act as very efficient filters for ridding the body of waste and toxic substances, and returning vitamins, amino acids, glucose, hormones and other vital substances into the bloodstream. The kidneys receive a high blood flow and this is filtered by very specialised blood vessels.</em>
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The answer is <span>polarized </span><span>state.</span>
Mitochondria and chloroplasts likely evolved from engulfed bacteria that once lived as independent organisms. ... Eukaryotic cells containing mitochondria then engulfed photosynthetic bacteria, which evolved to become specialized chloroplast organelles.
The answer is prokaryotes
The major function of the contractile vacuole of amoeba is osmoregulation. The solute concentration found in the cell of amoeba's cytoplasm is more than the solute concentration in the freshwater that surround the external part of the organism, thus, water enter the cell through osmosis. The contractile vacuole collect the excess water and expel it through an opening in the cell membrane. By doing this, the contractile vacuole maintains the water balance in amoeba. This how the contractile vacuole normally operate.
In a situation where amoeba is placed in seawater, then water from the cell cytoplasm will rush out of amoeba cell, because of the higher salt content of the surrounding medium. The contractile vacuole will respond to the situation by increasing its contraction and pumping water out the cell in an accelerated manner, this will lead to the shrinking of the cell.
Complete question:
In a separate study, 68 rock pocket mice were collected from four different, widely separated areas of dark lava rock. One collecting site was in Sonora, Mexico. The other three were in Chihuahua, Mexico. Dr. Nachman and colleagues observed no significant differences in the color of the rocks in the four locations sampled. However, the dark-colored mice from the three Chihuahua locations were slightly darker than the dark-colored mice from the Sonora population. The entire Mc1r gene was sequenced in all 68 of the mice collected. The mutations responsible for the dark fur color in the Sonora mice were absent from the three different populations of Chihuahua mice. No Mc1r mutations were associated with dark fur color in the Chihuahua populations. These findings suggest that adaptive dark coloration has occurred at least twice in the rock pocket mouse and that these similar phenotypic changes have different genetic bases.
How does this study support the concept that natural selection is not random?
Answer:
The study supports the concept that natural selection is not random because in different areas with the same or very similar environmental characteristics, the same phenotype was produced by different types of mutations.
Explanation:
All of the sampled animals are inhabiting dark substrate. Probably animals needed to camouflage to survive. Natural selection must have driven them to produce dark color, similar to the substrate color. So animals from the different regions suffered different mutations that drove them to have almost the same dark fur color. The environmental condition is favoring the same phenotype.
