Which term describes hair-like structures on the bodies of some worms that assist in movement and sensing the environment?

Which term describes hair-like structures on the bodies of some worms that assist in movement and sensing the environment?

• A. Bristles
• B. Cilia
• C. Suckers
• D. Mollusk

Answer: (A)

Hair-like structures on some worms that help with movement and sensing the environment are bristles, also known as setae. These tiny projections are usually aligned along each body segment and can be extended to grab onto the soil or substrate as the worm’s muscles contract, providing traction to push or anchor parts of the body for efficient crawling. They can also play a role in sensing touch or changes in the surroundings, giving the worm information about its environment. This idea is different from cilia, which are much smaller, beat in coordinated waves to move fluids or toward propulsion rather than providing the kind of traction needed for crawling. Suckers are adhesive organs seen in certain organisms like leeches, not a general feature of worm bodies, and mollusk refers to a whole group of animals, not a type of hair-like structure. So the term that fits these hair-like locomotion and sensing features is bristles.

Hair-like structures on some worms that help with movement and sensing the environment are bristles, also known as setae. These tiny projections are usually aligned along each body segment and can be extended to grab onto the soil or substrate as the worm’s muscles contract, providing traction to push or anchor parts of the body for efficient crawling. They can also play a role in sensing touch or changes in the surroundings, giving the worm information about its environment. This idea is different from cilia, which are much smaller, beat in coordinated waves to move fluids or toward propulsion rather than providing the kind of traction needed for crawling. Suckers are adhesive organs seen in certain organisms like leeches, not a general feature of worm bodies, and mollusk refers to a whole group of animals, not a type of hair-like structure. So the term that fits these hair-like locomotion and sensing features is bristles.