You repeat the test and obtain the same results. We know that there is an inefficiency of energy transfer from one trophic level to the next. If you found two apparently strongly competing species living together, provide three unique explanations for this observation. Desert plants often have a form of photosynthesis other than C3. Mutualism is arguably one of the most important species relationships we have studied.
All organisms modify their environment as a function of survival.
Some cause extensive changes. In this context, discuss the changes caused by humans. Traditionally the last sere of a succession was called the climax. Currently many ecologists feel there is no real climax sere.