Snails and insects belong to which group of organisms mammals

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

Up to what percentage of the world's flora consisted of cycads during the triassic period? 100% 75% 50% 20%

Is dna the same in every cell in the human body explain your answer