Just like a food chain, energy enters the food web at the trophic level of the producers, which can also be called autotrophs. In the desert, autotrophs are often some type of cactus, grass, or shrub.
The main purpose of the INTRODUCTION is to give a description of the problem that will be addressed. In this section the researcher might discuss the nature of the research, the purpose of the research, the significance of the research problem, and the research question(s) to be addressed. Three essential parts of a good introduction are: RATIONALE.
Introduction. The introduction is the first paragraph in your essay, and it should accomplish a few specific goals. 1. Capture the reader's interest. It's a good idea to start your essay with a really interesting statement, in order to pique the reader's interest.