Transport proteins located in the cytoplasmic membrane are necessary when
A. diffusion will not allow adequate amounts of a substance to enter the cell.
B. movement into the cell is against a concentration gradient.
C. the level of nutrients in nature is very low.
D. nutrient concentration is very low in the environment, is higher inside of the cell, or diffusion is not possible.
Answer:D
Transport proteins located in the cytoplasmic membrane are necessary when
A. diffusion will not allow adequate amounts of a substance to enter the cell. B. movement into the cell is against a concentration gradient. C. the level of nutrients in nature is very low. D. nutrient concentration is very low in the environment, is higher inside of the cell, or diffusion is not possible.