Which of the Following Statements About the Protonephridia of Freshwater

question 63

Multiple Choice

Which of the following statements about the protonephridia of freshwater flatworms is CORRECT?

• A)Fluid from the body enters the protonephridia without first being filtered.
• B)Protonephridia are surrounded by a capillary network to allow for selective reabsorption and secretion.
• C)The urine leaving the body of a freshwater flatworm is more concentrated than its body fluids.
• D)Muscular contractions drive fluid movement through the excretory tubules.
• E)The fluid passing through the tubules is not modified before excretion.

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Definitions:

Steroidal

Relating to or characterized by the presence of steroids, which are a large class of organic compounds with a characteristic molecular structure.

Cell Membrane

The outer limit of a cell that is thin and selectively permeable. It controls the movement of substances into and out of the cell.

Hormone

A chemical secreted by a cell that affects the functions of other cells.

Steroidal Hormones

Hormones derived from cholesterol, including sex hormones and corticosteroids, which play vital roles in body functions.