Which motion of particles across a membrane requires energy? from high concentration to low concentration
from low concentration to high concentration
with no concentration gradient
through dynamic equilibrium

An organism has the following traits multicellular cant photosynthesize has a skull. wht kingdom does this organism most likely belong too?

Which statement correctly describes other ways in which nebulae and stars are different? a. a star always has a higher density than a nebula. b. stars can form inside a nebula but a nebula can never be produced by any star. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star. reset submit

What household products contain algae?