Why are capillarie and not arteries or veins found in alveoli, nephrons, and villi

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

Which sequence correctly shows the path of carbon dioxide during repiration?

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