Pollution in the will have the greatest effect on human health.

a. troposphere
b. stratosphere
c. mesosphere
d. thermosphere

The correct answer is - a. troposphere.

The pollution of the troposphere has and will have even bigger effect on the human health. This is the lowest layer of the Earth's atmosphere, it is the layer where humans live, where all the activities are done, it is the thickest of all the layers of the atmosphere of our planet, and also the only layer that enables the conditions needed for life on our planet. Unfortunately, most of the pollution caused by the human activity is directly affecting and disturbing the balance of this layer and it is already evident that it has big negative effect on the human health and in the future it will be even bigger.