What is proof that all living things have a common ancestor?

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

Do you think the gene eef1 alpha1 supports cell theory? explain your response.

You want to cultivate some exotic plants at your farm. however, the climate is chillier than the temperature range favorable to the crop. which is the best method to use for the cultivation of this exotic crop? a. use a crop rotation method b. use a lot of fertilizer c. prepare the seed bed properly d. use a greenhouse e. use irrigation