AP BIOLOGY

Detailed explanation-1: -A lubricant such as oil and grease is introduced between the surfaces of contact thus reducing friction.

Detailed explanation-2: -Solution : The slimy substance secreted by these animals reduces the friction between their bodies and the surface of the ground, thus helping in the movement of these animals, e.g., the slimyy mucus secreted by foot of snaill makes the track slippery and helps it to move smoothly over it.

Detailed explanation-3: -The slimy substance secreted by earthworm helps it to move smoothly and swiftly on the ground. It has hair-like projections, connected with the muscles under its body, that fixes its parts on the ground. These structures are termed as bristles. Q.

Detailed explanation-4: -Many earthworms secrete a mucus (coelomic fluid) that helps them to move more easily through the soil. In some burrowing species, this fluid forms a cement-like substance that lines their burrows to help keep the walls from collapsing.