Which soil properties is not influenced by microorganism activity? a. soil acidity b. amount of organic matter c. nutrient levels d. none of the above

Next pretest: evolution select the correct answer in a laboratory population of flies, the female flies are gray and the males are yellowish gray. biologists observed that all the male flies had an equal chance for reproduction, but the male flies with the brightest colors were more likely to successfully reproduce. what phenomenon could explain such a change? a sexual selection b. disruptive selection c. stabilizing selection d. directional selection

Amino acids contain the elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. of the 20 amino acids found in humans, 11 are called "nonessential" because they can be manufactured by the body when needed. which elements in these 11 amino acids are commonly obtained from the metabolism of sugar molecules?

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -