4 is c and 5 I think is a
D. is the heterotrophism hypothesis, but it is questionable that it is the "strongest" hypothesis. The alternately proposed option is autotrophism, which is the ability of an organism to obtain its own nutrients without relying on other organic materials. The potential advantage of autotrophism is its relatively simpler structure, making a simpler organism viable because it is potentially less complex and "easier to create."
