At least how many types of organisms inhabit the earth? The measure of the variety of organisms present in different ecosystems is called what? How many types of plants are known to biologists? Biological classification is a method by which whom divide orgnisms into groups and subgroups? Systemized knowledge from observation and experiments is? The experiments in science are made to determine the principles of? What Man have to become in order to live? In history man …………between edible and non edible? The scientific method in which biological problems can be solved is?