The downward pull on an object due to gravity is the object’s

When an object falls, it is pulled down by the force of gravity. This constant force, called the weight, causes the object to accelerate as it moves downward. This acceleration is the same for all bodies (all bodies on the same planet or moon), and it is called the acceleration due to gravity.

The arrangements of lipids in the membrane makes the cell semi permeable .

A) early horses is your answer