Which term is described as disc-like structures used to attach to surfaces?

Which term is described as disc-like structures used to attach to surfaces?

• A. Bristles
• B. Cilia
• C. Worm cast
• D. Suckers

Answer: (D)

Suckers are disc-like structures that attach to surfaces by suction. The broad, flat shape creates a seal against the surface, and when the muscles contract to pull air out from inside the cup, a negative pressure forms. That pressure difference pulls the surface toward the disc, giving a strong grip even on smooth or wet surfaces. The disc design distributes the holding force over a larger area, which helps maintain the seal and keep the attachment secure. Bristles are hair-like projections used for grip or movement, not for suction-based attachment. Cilia are tiny hair-like structures that move fluids or particles, not for sticking to surfaces. A worm cast is just the castings produced by earthworms, not an attachment structure.

Suckers are disc-like structures that attach to surfaces by suction. The broad, flat shape creates a seal against the surface, and when the muscles contract to pull air out from inside the cup, a negative pressure forms. That pressure difference pulls the surface toward the disc, giving a strong grip even on smooth or wet surfaces. The disc design distributes the holding force over a larger area, which helps maintain the seal and keep the attachment secure.

Bristles are hair-like projections used for grip or movement, not for suction-based attachment. Cilia are tiny hair-like structures that move fluids or particles, not for sticking to surfaces. A worm cast is just the castings produced by earthworms, not an attachment structure.