In this layer of earth's atmosphere, hydrogen and helium are the prime gases and are only present at extremely low densities. what is this layer of the atmosphere called? a) exosphere b) ionosphere. c) mesosphere d) thermosphere

The answer would be the EXOSPHERE. The exosphere is the highest layer of the atmosphere. This layer merges with space and the air is extremely thin. Molecules of air here always escape from the from the exosphere to space. This is also the layer where satellites orbit the Earth. 

The answer a. 

Iread this book last year so take this with a grain of salt.gene jumps from the tree to compete with finny due to the fact that gene is always trying to do better than finny. he is put under the grasp of peer pressure due to finny almost forcing him to do this. ever since he first jumped finny kept pressuring him to jump since he thought gene enjoyed jumping.rather than uses this answer you should probably just reread chapters 3-4