Food chains and webs typically do not have more than four levels of consumers. Why not? A. Since only 10% of available energy is passed from one level to the next, there would not be enough available energy to be passed on if there were more than four levels

B. All available energy is passed from one level to the next, however there are too many carnivores to share the energy

C. Since only 50% of available energy is passed from one level to the next, there would not be enough available energy to be passed on if there were more than four levels.

Put the following steps of the convection process in the correct order. 1. gravity pulls cooler matter downward. 2. the matter expands and decreases in density. 3. an up-and-down flow of matter produces a convection current. 4. matter is heated. 5. warmed matter is forced upward. question 2 options: a) 4, 2, 5, 1, 3 b) 2, 4, 3, 1, 5 c) 3, 2, 5, 4, 1 d) 1, 4, 2, 5, 3

(select all the correct choose each statement that is scientific. - the opinions of randomly selected participants in a survey prove the idea that global temperatures are not increasing on earth. - the universe's average temperature and rate of expansion support the idea that it began as one super-dense and hot mass 13.8 billion years ago. - ocean tides are caused by the uneven gravitational pulls of the moon and sun on different parts of earth. - human life is more valuable than other forms of life on earth because humans are more intelligent than other organisms.

Milk production during breastfeeding is increased by the suckling of a newborn from his mother's nipple. this type of feedback mechanism best describes a positive or negative