Question

read the opinion below. everyone should wear helmets when riding bicycles. select the reason that best supports this opinion. most bicycle helmets are built with holes in them to help riders keep cool. helmets protect your head if you get into a bike accident. submit

Explanation:

The opinion is that everyone should wear helmets when riding bicycles. The first reason "Helmets protect your head if you get into a bike accident" directly supports the importance of wearing helmets for safety, which is the core of the opinion. The second reason is about the design feature (holes for cooling) which is more about the helmet's functionality rather than a direct support for why one should wear it (the safety aspect is more crucial for supporting the opinion of wearing).

Answer:

Helmets protect your head if you get into a bike accident.