This is the role of a species in an ecosystem, consisting of such things as what it eats, when it eats, and where it lives. i can not find the

The correct answer is niche.  

A niche in ecology refers to the fit of a species thriving under particular environmental circumstances. The ecological niche illustrates how a species or population reacts to the distribution of resources and competitors, and how it can turn alters those similar elements.  

The kind and number of variables constituting in the dimensions of an environmental niche change from one species to another and the comparative importance of specific environmental variables for a species may change on the basis of the biotic and geographic contexts.  

the cell cycle is the final answer! : )

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds