The principle stating that the oldest rocks occur on the bottom of an undisturbed rock sequence is known as

Match the reproductive structures based on their function and the system to which they belong. egg ovary sperm vas deferens vagina fallopian tube testis urethra

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.

Which of the following may one conclude from a map that shows the average ph value of rainfall in the u. s.? acid rain is a more serious problem on the east coast. acid rain falls equivalently across the continental u. s. there are more factories on the west coast. the midwest has fewer forests than the rest of the u. s.