Birds, unlike mammals, do not have separate exits for urine and feces. Both waste products are eliminated simultaneously through the cloaca. While mammals excrete nitrogenous wastes mostly in the form of urea, birds convert it to uric acid or guanine, which reduces water loss in comparison.
Need more info can’t really get an answer out of this sorry :/
Answer:

Explanation:
Mechanical advantage is given by the ratio of output force by input force.
= Output force = 
= Input force = 
So,

The mechanical advantage of the pulley's is
.
Evolutionary biologist hope this helps