Question

What happens when ATP supplies energy for thin filaments in a muscle fiber to slide over the thick filaments?

Answer 1

2. A. Sebaceous glands
Lipids are macromolecules which provide insulation. 
A macromolecule is a large molecule. There are four groups of macromolecules: carbohydrates, proteins, nucleic acids and lipids. Lipids consist of glycerol and fatty acids and are constructed from fats, oils, waxes, phospholipids and steroids. A lipid's function is to insulate the body and provide warmth in cold conditions. It can be concluded that a person with very little body fat gets very cold easily and a person with a lot of body fat gets very warm very quickly.

3. B. Thinner

Answer 2

The answer to your questions are

1. a
2. a
3. b