in a pond food chain that includes tadpoles, algae, turtles, dragonflies, and frogs, which one is the primary consumer

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).

A. ​it generates energy from carbohydrates.b. it requires activation by oxygen.​c. ​it is used by cells to dispose of excess electrons