Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?

When graphing the phenotypes of a trait controlled by many genes and the environment, the line showing the frequency of each phenotype resembles .a. a horizontal, straight line;b. a vertical, straight line;c. the letter T;d. a bell shape;e. a circle

Skin color in humans is at least partially hereditary; dark-skinned parents tend to have dark-skinned children. But humans come in a range of skin tones. Which extension of Mendel's model accounts for the hereditary variation in human skin color?

Tail length in a certain species of armadillo falls along a continuum; a plot of tail length versus frequency displays a normal distribution. Assuming that environmental factors do not play an important role in determining tail length, this type of variation probably reflects __________.

Heart disease, diabetes, cancer, alcoholism, and many mental illnesses can best be described as __________.

Mendel's theory of inheritance __________.