The opioid propeptides

A) include the endorphins and the endomorphins.
B) are made in the terminal button and cleaved by enzymes into the opiate peptides.
C) are processed by proteases into both opiate and non-opioid peptides.
D) are referred to as the "enkephalins."

The correct answer is option C) "are processed by proteases into both opiate and non-opioid peptides".

Explanation:

The opioid propeptides, as well as any other propeptides, is a protein precursor that needs to be excised into a smaller form to acquire its active form.  The opioid propeptides are processed by proteases into both opiate and non-opioid peptides, where the latter could be active or non active. Opiate peptides are enkephalins, endorphins, and dynorphins that act by blocking secondary systems, such as the ones that cause pain perception.

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.