What is the difference between normal tissue and cancer

Cellular communication is an important aspect in cancer prevention because a group of cells growing rapidly can be recognized and halted before given the chance to grow out of control. It is well known that in a cancerous cell, one of the first mutations to occur is in its ability to communicate with its surroundings. In absence of this characteristic cells are able to grow rapidly and invade surrounding tissues even though they may be receiving, but not processing appropriately, external signals to halt growth.

significant amounts of nitrogen oxides, carbon monoxide, and other pollution

explanation:

passenger vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. in 2013, transportation contributed more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air.