EXPLAIN Why is there a limit on the number of trophic levels that can exist within an ecosystem?
O a. The number of trophic levels is limited by the amount of available energy.
b. There would not be enough space for more organisms.
c. There would be too much competition among organisms.
Od. There is no limit to the number of trophic levels that can be added
within an ecosystem.

20 in the formula no3, what does the subscript 3 mean?

Which is the best way to define a common in environmental science a. a worthless resource b. shared resource c. a rare resource d. a typical resource

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.