The rider tugged on the of her horse to make him slow down.

Reins.

Explanation:

The rider tugged on the reins of her horse to make him slow down.

answer; (d) i believe the best answer is ; ///people said that man could not fly, but in 1903, orville and wilbur wright made the first sustained powered flight in a heavier- than-air machine;

in my opinion, ap calculus was the most difficult. i often struggled with it a lot. however, i have gotten a lot better.