Because the three-horned alien is heterozygous, we know that three must be dominant to four, because the gene for the three horns is "hiding" the gene for four horns. Therefore, the three-horned alien has the genotype Tt (T for three horns, and t for four horns). The four horned alien must be tt, because that is the only way that a recessive trait may be seen. If you solve the punnet square on a cross between Tt and tt, you end up with half three (heterozygous) and half four (homozygous recessive) it is a bit easier to explain with something a little "closer to home" if you want me to explain it again, just say so, I don't mind!
Answer:
A, pleiotropy.
Explanation:
Pleiotropy - genes that have multiple phenotypic effects. Remember that phenotype means a physical characteristic caused by a gene, such as eye color or fur patterns.
Incomplete dominance - when neither allele is dominant and they mix together in the phenotype. A popular example is a red flower crossing with a white flower and resulting in a pink flower.
Epistasis - when two genes contribute to the phenotype, but one gene completely masks another gene. An example would be labrador fur colors.
Multiple alleles - 3 or more alternative forms of a gene, but only 2 alleles can occupy an organism. An example is blood type.
Hope this helps!
Whales play an important role in stabilizing the aquatic food chain and reproduction of other species.
As more whales are killed the food distribution in the ocean becomes destabilized and causes changes in the food supply of many other kinds of marine life.
Whales are vital to the food chain, stabilising food flow and maintaining a healthy ocean.
As such, the rapidly decreasing whale population will have major effects on the ocean's ecosystem.
Believe it or not, whale poop also serves quite an important purpose to the ecosystem.
It would give nature a place to fight back, and become more healthy, and less hindered. Cities mess up the evaporation cycle, and because of parks, the water is able to be soaked up by grass, and then released through evaporation. When it rains over a city, the water goes into gutters, and becomes more polluted.
<span>The question is asking how over-irrigation is damaging to soil. Over-irrigation means that too much water is being delivered to the soil, and too much water can wash some other important ingredients out - such as organic material. Therefore, the correct answer is:
a. It reduces the amount of organic material in soil.</span>
