Answer:
Changes in gene expression
Explanation:
A seedling is a young plant sporophyte creating out of a plant incipient organism from a seed. Seedling improvement begins with germination of the seed. A common youthful seedling comprises of three fundamental parts: the radicle, the hypocotyl, and the cotyledons.
Since an animal only becomes more complex, and not simpler, an ancestor to all organisms would have to be the most simple and primitive organism.
Answer: radiation i think
This is because bacteria are single-celled organisms.As opposed to animals and plants, which are multicellular organisms, bacteria are not - they consist of one cell only. This is what makes the entire process of binary fission much simpler than mitosis in plants and animals - because of the number of cells these organisms contain.