Question

which of the following is not matter?
a sound
b plant
c cloud
d feather

Explanation:

Matter is anything that has mass and occupies space. A plant (b) has mass and takes up space, a cloud (c) is made of water droplets (has mass and volume), and a feather (d) has mass and occupies space. Sound (a) is a wave, a form of energy, and does not have mass or occupy space, so it is not matter.

Answer:

a. Sound