60% of the human adult body is water. According to H.H. Mitchell, Journal of Biological Chemistry 158, the brain and heart are composed of 73% water, and the lungs are about 83% water. The skin contains 64% water, muscles and kidneys are 79%, and even the bones are watery: 31%.
As it mostly occurs on a surface where an ecosystem has previously existed. Primary succession only occurs on a surface where no ecosystem existed ever before!
He tested the seed color and shape. At the same time Gregor Mendel focused his search on seed size, flower color, seed coat color, pod size, immature pod color, flower position and pea plant height.
To describe the results he drew, he coined the terms 'recessive' and 'dominant'.