note:
Gymnosperms possess several key evolutionary innovations compared to earlier groups such as the clubmosses and ferns. They produce sperm-containing pollen, which is carried through the air by the wind to the female. This innovation has freed these plants from the need for water for sexual reproduction.
The correct answer to this question is this one: they lacked oxygen. The earliest organisms were completely heterotrophic in nature because of the reason that they lacked oxygen. <span>A heterotroph is an organism that cannot fix carbon and uses organic carbon for growth. </span>
Inbreeding is increased due to the small number of individuals in the population. Selective breeding; > Humans can cause a decrease in genetic diversity too. ... > Selective breeding involves choosing which animals or plants to breed so that they have certain benefits.
