In order to maintain its homeostasis, human cells must have a higher concentration of sodium ions outside the cell than inside the cell. in addition, the concentration of potassium ions must be higher inside the cell than outside the cell. which of the following forms of cellular transportation human cells maintain their sodium and potassium concentration?
a. diffusion
b. a cell membrane pump
c. osmosis
d. passive transport

Deer cave cannot support photosynthesis is as not enough sunlight is present. in spite of this, it still has a complex food chain. what is the energy foundation of this food chain?

Elephants in the savanna regions of africa dig holes in dried up river beds to reach water lying just below the surface. these holes provide drinking water for other animals as well. so, without the elephants, many animals might otherwise die from lack of water during the dry season. the location in which the elephants live is an example of a/n and the role they play in creating water holes is an example of a a) ecosystem; habitat b) community; niche c) habitat; niche d) niche; habitat

Aristotle classified animals according to their a. habitat and mating behavior c. mating behavior and relatedness b. habitat and physical differences d. physical differences and mating behavior