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!
DNA contains the instructions needed for an organism to develop, survive and reproduce. To carry out these functions, DNA sequences must be converted into messages that can be used to produce proteins, which are the complex molecules that do most of the work in our bodies.
Answer:
A) Light pollution both attracts and repels migratory birds
In addition to the many hazards that exist in urban areas, cities typically lack the food resources and cover that birds need during migration or when raising their young. ... Darkening skies at night during migration season makes it easier for birds to navigate.
Explanation:
Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by availability of food. It occurs mainly in the northern hemisphere, where birds are funneled on to specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea.
The answer is A none of the following
Http://www.collective-evolution.com/2014/07/07/new-study-finds-88-percent-of-earths-ocean-surface-no...
This should be of use here.