What is the likely long-term consequence of an increase in the relative percent of greenhouse gases in earth’s atmosphere?
a. earth’s average temperature will increase.
b. earth’s average temperature will decrease.
c. earth will experience greater temperature extremes.
d. earth’s average temperature will be unaffected.

Correct A). Earth’s average temperature will increase.

Green house gases are those gases, which are present in the air that have the ability to trap heat of the earth's surface. Gases like carbon dioxide and methane are  known to be found naturally play an important role in earth's climate. If they are not found the earth' s climate would be too cold creating problem for survival of life on the earth.

They absorb and emit the radiation in the thermal infrared range. These gases act like a blanket and save earth surface from infrared radiation by absorbing them and prevent them from escaping out of the earth surface.

But due to increased in the concentration of green house gases like carbon dioxide and methane in the environment due to pollution and deforestation is causing a great problem, which result in a global warming, which is a great concern for all the people on the planet. It will increase the annual global temperature which will result in the melting of glaciers. So, the issue of global warming should be taken seriously and adequate measure should be taken to control it.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds