Scientists have studied patterns of development and differentiation of cells and tissues in a wide variety of species. Which statement describes the role and function of master control genes, or Hox genes, in many species?
A. They often are identical and perform identical functions in different species.
B. They are unique and perform different functions in different species.
C. They exist and function only in humans and a few other species.
D. They exist and function only in insects and a few other species.

B

Explanation:

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.

they dont have any evidence