Explain what happens to the bands a, i,h when aconraction occurs
in the muscles.

The functional unit of a muscle cell is known as a "sarcomere" which covers the distance between the two Z-lines.

The sarcomere consists of A-zone which contains both thick and thin filaments, H-zone which contains only thick filaments and I band which contains only thin filaments.

During muscle contraction, thick and thin myofibrils slide over each other due to which the distance between two z-line get reduced. The H and I zone gets shortened but A zone does not shorten but come close to other A- bands and disappears.

answer; /// the correct )

relative humidity, temperature and dew point -- are bound together in the mathematical relationship below. relative humidity changes when temperatures change. because warm air can hold more water vapor than cool air, relative humidity falls when the temperature rises if no moisture is added to the air. so i would say a