Hi im from America and i need help with some biology ap work.Thank You =]

Hi im from America and i need help with some biology ap work.Thank You =]
1.To investigate the structure and function of ecosystems,ecologists may construct a microcosm using organisms and materials from the ecosystem.Properly constructed,these model systems should be self-sustaining.If you remove the primary producers from the microcosm,would you predict that your model would continue to be self-sustaining?Explain.
2.Species interactions affect the distribution and abundance of populations.Summarize experimental evidence that population size for snowshoe hares depends on both predation rates by lynx and competition for food among hares.
3.Using your knowledge of ecosystem structure and function,compare the trophic structure if a desert to that of a temperate hardwood forest.Include the relative number (not exact) of organisms and energy availability for the different trophic levels.
4.What is the difference between primary succession and secondary succession?
Thank you so much!