What was Anton van Leeuwenhoeks contribution in the development of cell theory?

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 type of appendages do sponges cnidarians roundworms annelids mollusks arthropods echinoderms and vertebrate have? jointed, not jointed, absent  

The function of the excretory system is to control homeostasis and