Why could the spectral analysis of stars not be done before the identification of spectra of the elements?

The earth consists of a variety of different organisms. despite their diversity, however, some similarities on the structural and metabolic levels may be seen. these similarities can be attributed to a. similarities among organisms in their proteins and nucleic acids. b. the ability of organisms to readily adapt to sudden environmental changes. c. similarities in organisms' habitats and niches. d. the ability of all organisms to interbreed and produce new species.

An easy way to calculate the amount of energy available at each level is to what?

List five ways we are indebted to phytoplankton