The diver in this photo is a living system. the scuba, or self-contained underwater breathing apparatus, gear is a system of air exchange. how are these two systems interacting?

Hurry which of these is true about index fossils? a) are very scarcely found b) used as guides in relative dating c) found in the youngest layer of the rock d) used as reference points in absolute dating

Mike has a problem with his testosterone. he is unable to produce enough. which will most likely be affected by his inability to produce testosterone? check all that apply.

Deer cave cannot support photosynthesis is as not enough sunlight is present. in spite of this, it still has a complex food chain. what is the energy foundation of this food chain?