Crawfish have a few diseases.

• A. True
• B. False
• C. Not Applicable
• D. Common

Answer: (A)

Crawfish can be affected by multiple diseases, so the statement is true. Like other aquatic species, they are exposed to a range of pathogens—bacteria, fungi, parasites, and sometimes viruses—and outbreaks can occur, especially under stress from crowding, poor water quality, or suboptimal conditions. Crayfish plague caused by Aphanomyces astaci is a well-known example, along with other infections that can impact growth, shell condition, and survival. Because there are several distinct diseases that can affect crawfish, saying they have a few diseases accurately reflects reality.

The other options don’t fit because saying they do not have diseases ignores well-documented pathogens affecting crawfish, and “not applicable” isn’t appropriate for a factual biological statement. “Common” would address how frequently diseases occur rather than whether diseases exist at all.