Question

Choose the correct option(s) in the context of nutrient exchange and waste elimination in multicellular organisms.

• A. Exchange of life-supporting nutrients and waste elimination takes place with the external environment directly.
• B. Exchange of life-supporting nutrients and waste elimination takes place with the external environment through the extracellular fluid.
• C. The extracellular fluid exists outside of the muscle cells and serves as the medium for vital exchanges with the external environment.
• D. The plasma is the component of the extracellular fluid that surrounds muscle cells.

Answer 1

Answer: (B), (C)

The correct options are
B Exchange of life-supporting nutrients and waste elimination takes place with the external environment through the extracellular fluid.
C The extracellular fluid exists outside of the muscle cells and serves as the medium for vital exchanges with the external environment.

Single-celled organisms like Paramecium directly obtain essential nutrients and oxygen from its external environment and eliminates waste back into the same environment. Muscle cells, however, cannot have similar vital exchanges directly with the external environment as they are isolated from it. To meet the need for life-supporting nutrients and waste elimination, the extracellular fluid (ECF) comes into play. Muscle cells are in direct contact with a fluid internal environment present outside the cell, called the extracellular fluid. ECF has two components - the plasma and the interstitial fluid. It is this interstitial fluid which surrounds the cells. The interstitial fluid exchange nutrients and wastes into the blood plasma, which acts as a conduit for the cells of multicellular organisms with the external environment.