Answer:
Food webs and food chains.
A food web describes the flow of energy and nutrients through an ecosystem, while a food chain is a linear path through a food web
Answer:
a plant that is characterized by the presence of conducting tissue.
Explanation:
Nope, because they serve no purpose on earth
The answer is: massive stars create a lot of heavier elements. They produce much of the carbon and oxygen which is hugely important for humans and water respectively.
The correct answer would be the last one: "evolved from past organisms." This theory basically just states that all living organisms evolved from a single common ancestor. Hope this helped! :)