Select the most correct statement.

A. Maintaining boundaries: Maintaining boundaries refers to the separation between internal and external environments, such as the plasma membrane or skin, and is not directly related to removing carbon dioxide.

B. Excretion of metabolic waste: Expiration removes carbon dioxide, a byproduct of cellular respiration, from the body. This is a primary example of excreting metabolic waste to maintain proper internal chemical balance.

C. Responsiveness: Responsiveness is the ability of the body to detect and react to changes in the environment, such as moving away from a stimulus, which does not involve carbon dioxide removal.

D. Metabolism: Metabolism encompasses all chemical reactions in the body, including producing carbon dioxide as a byproduct. However, the act of exhaling carbon dioxide specifically exemplifies waste excretion, not metabolism itself.

A. The cells will shrink at first, but will later reach equilibrium with the surrounding solution and return to their original condition: If the solute cannot cross the membrane, the cells cannot regain water through solute equilibration, so they will not return to their original size.

B. The cells will show no change due to diffusion of both solute and solvent: In a hypertonic solution where the solute is impermeable, only water can move, so diffusion of solute does not occur and the cell will be affected by water loss.

C. The cells will lose water and shrink: Water moves out of the cell by osmosis to balance the higher extracellular solute concentration. The loss of water causes the cells to shrink, a process called crenation.

D. The cells will swell and ultimately burst: Swelling occurs in a hypotonic solution where water enters the cell due to lower solute concentration outside. In a hypertonic solution, the opposite occurs, so bursting does not happen.