Question

complete the sentence.
some ____ carry signals that tell ____ to contract.
nerves...tendons
tendons...nerves
nerves...muscles
muscles...nerves

Explanation:

To solve this, we recall biological knowledge: Nerves transmit signals (like motor signals) that instruct muscles to contract. Tendons connect muscles to bones and don't contract based on nerve signals in this context, and muscles don't send signals to nerves for contraction. So the correct pair is nerves carrying signals to muscles.

Answer:

nerves... muscles (the option with "nerves... muscles")