Shleiden and Theodor Schwann were the first to recognize that all plants and animals are composed of cells.
Hope this helped :)
I think your anwser would be all of the above but you don't have it
D) each parent passes only one factor for each trait to its offspring
Answer:
Due evolution, discoveries and having both characteristics.
Explanation:
The Kingdom of Life change due to evolution in the body of organisms, discoveries of new organisms that are different from plants and animals. There are some organisms that have both plant and animal characteristics so it can't be placed in plant or animal kingdom so that's why the kingdom of life changes from two kingdom system to 5 kingdom system.