In general, less complex animals are:
a. more likely to rely on specialized mouth parts for digestion.
b. more likely to perform extracellular digestion than intracellular digestion.
c. more likely to have a gastrovascular cavity than to have a digestive tract.
d. more likely to have two body openings than to have one body opening.

in 1972 the fluid—mosaic membrane model of membrane structure was proposed based on thermodynamic principals of organization of membrane lipids and proteins and available evidence of asymmetry and lateral mobility within the membrane matrix [s. j. singer and g. l. nicolson, science 175 (1972) 720–731].

the water is warmed up by the sun and then it evaporates into the atmosphere. the sunlight warms the water by its heat. water is then cooled down and condensation takes place. the water then finally returns back to the earth by the process of precipitation in the form of rain or ice.

explanation: