Select the pair of structures that best shows how plant cells are different from animal cells. a. cytoplasm and mitochondria b. chloroplasts and cell walls c. nuclei and centrioles d. ribosomes and cell membranes

What is a population? a. all the members of the same species living in the same ecosystem at the same time b. the number of a species living in the same ecosystem over a period of time c. the total number of organisms living in an ecosystem at a point in time d. all the members of a food web in the same ecosystem