Photosynthesis cannot happen without

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

The table shows dates and appearance of index fossils. which rock layers can be dated most precisely? a) a layer containing both a fossil 4 and a fossil 3 b) a layer containing both a fossil 2 and a fossil 3 c) a layer containing both a fossil 1 and a fossil 4 d) a layer containing both a fossil 1 and a fossil 2

The breakdown of food is accomplished by enzymes. a. physical b. chemical c. mechanical d. none of the above