3. How does oxygen cross into the cell?

Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

she will be charged $6

step-by-step explanation:

48 dollars divided by 200 beads equals .24 dollars a bead

.24 multiplied by 25 more beads equals 6 dollars as the total cost