On what bases are galaxies classified?
a) density and volume
b) mass and temperature
c) shape and structure
d) temperate and size

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