How many molecules of water are formed when four amino acids join

Which mantle is under the crust the upper mantle or the lower mantle i think it's upper let me know if i'm right

During a hot day, warm and moist air rises and cools in the atmosphere. which even would occur next on such a day? a. condensed droplets would gather to become water vapor. b. water vapor would condense into tiny droplets. c. water droplets would evaporate to form rain and snow.

What is usually (but not always) related to the metabolic processes of living organisms in its organic form?