Answer: B
Explanation:
Ammonia is so toxic that it can be transported and excreted only in large volumes of very dilute solution. As a result most terrestrial animals simply don't have access to sufficient water to routine excrete ammonia.
The main advantage of urea is its very low toxicity. Animals can transport urea in the circulatory system and store it safely in high concentrations. Also much less water is loss when a given quantity of nitrogen is excreted in a concentrated solution of urea than would be in a dilute solution of ammonia.
Variation is number of alleles for the wing color of the peppered moths. The wing color ranges from pure white to pure back.
Selection pressure is predation by birds.
Explanation:
In the wake of the industrial revolution, white-winged peppered moths had a large allelic frequency in the population compared to black-winged peppered moths. However, when the environment changed due to soot produced by industries (making the environment darker) white-winged peppered moths reduced while that of black moths increased.
This is because black moths were able to blend in and camouflage in the dark environment than white-winged peppered moths that stood out to their predators. Black moths, therefore, had an increased chance of reaching adulthood and passing their genes to the next generation. This increased the allelic frequency of black-winged peppered while that of white-winged moths reduced in the population.
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The same number <span>chromosomes are there in a maize egg cell nucleus as compared to a maize pollen cell nucleus</span>
They lack true tissues and organs and have no body symmetry. hope it helps