If we increased the enzymes, our food would break down too fast to process it. If there were no enzymes, the food wouldn't break down. Enzymes are so important, that without them in our saliva, we wouldn't be able to swallow or chew our food.
For offspring of to dominant appearing parents to appear recessive, both parents must be heterozygous, meaning they each have one dominant and one recessive allele. About 25% of their offspring will exhibit the recessive trait.
The greatest cause of the worldwide loss of species is human activity. I think
The directional selection is the type of natural selection, in which an extreme phenotype is promoted due to the changes in the environment. This causes the changes in the allele frequency and the shifting of the phenotype in a particular direction. In this condition, one of the extreme phenotypes are promoted, which result in the shifting of genotypic frequency either of the homozygous characteristics.
