In an ecosystem, each trophic level receives energy from the level below it. What is the source of energy for the first trophic level?

The finches on the galapagos island were similar in form except for variations of their beaks. darwin observed that these variations were useful for: attracting a mate defending territory building nests gathering food

How have high taxes on tobacco products impacted the number of people who use them? a. the number of tobacco users has increased. b. the number of tobacco users has decreased. c. the number of tobacco users has not changed. d. the number of adolescent tobacco users decreased, while the number of adult users increased

When listening the levels of orginization in orginisims from the smallest to most complex , which level is just below organs in complexity