Question

which is composed of alkynes?
acetylene
margarine
rubber tires
polystyrene cups

Explanation:

Alkynes are hydrocarbons with carbon - carbon triple bonds. Acetylene is the simplest alkyne with the formula C₂H₂. Margarine is a fat product, rubber tires are made of polymers from isoprene and other compounds, and polystyrene cups are made from polystyrene polymer, none of which are alkynes.

Answer:

A. acetylene