Mark argues that proteins within the body have two functions structure and transport sarah disagrees which significant function of proteins did mark omit from his list

Proteins are large complex compounds made up of one or more polypeptide chains.  

They play many major roles in living organisms:

Structural role: They are called building block of the body. They provide strength and structure to the cell. For example, keratin protein is found in nails, hair, and skin, collagen can be found in connective tissue et cetera.

Transport: They help in transport of material across the cell membrane. They form carriers and channels across the lipid bilayer which assist the transport of materials across it.

Immunological role: Antibodies or immunoglobulins are primarily protein in nature which helps our body to fight against a pathogen.

Biochemical reactions: In living organisms, biochemical reactions are majorly aided by enzymes which are mainly protein in nature (except ribozyme).

Chemical messenger: Proteins also occur as chemical messengers in the form of hormones such as insulin et cetera.

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.

bal is blood alcohol level. bac will normally be higher in a person with more body fat. so the answer to your question would be, as body fat decreases, the increasing rate of bal decreases.