CBSE Class 9 Answered

Coelomate animals means animals possessing a fluid-filled cavity called coelom.

Sedentary animals are animals or organisms that remain or live in one area. They are usually attached to a surface and not moving freely, such as a barnacle or sponge.

Appendage is a part or organ, such as an arm, leg, tail, or fin, that is joined to the axis or trunk of a body. It  is an external body part, or natural prolongation, that protrudes from an organism's body, such as a vertebrate's limbs. In invertebrates, appendage is a general term that covers any of the homologous body parts that may extend from a body segment. These include antennae, mouthparts, wings etc.

Appendages are usually present in pairs. For example - Humans have 2 hands and 2 legs.