I believe the answer is: $3.20 per kilogram.
This is a question of unit rate.
The arrangement of the layers of the atmosphere from the ground to the outer regions above the ground is troposphere, stratosphere, mesosphere, thermosphere, ionosphere and exosphere. The UV is said to be absorbed by layers thermosphere, mesosphere and stratosphere. Answer is B.
Answer: yes
Explanation:
Before the drift, South America, Africa, Arabia, Madagascar, India, Australia, and Antarctica were once incorporated in Gondwana land 600 million years ago.
I imagine, it's A, they get a sense of the history of the area they are investigating.