Which of the following statements about the earth’s atmosphere is true?

a.
in the past few decades, carbon dioxide levels have been rising.

b.
in the past few decades, carbon dioxide levels have been falling.

c.
a recent increase in carbon dioxide levels can contribute to a long-term cooling of earth’s climate.

d.
a recent decrease in carbon dioxide levels will increase plant growth on earth.
and this one

which statement describes how el niño contributes to climate trends on earth?

a.
a shift in trade winds in the pacific causes a large mass of cold water to replace warm water, bringing in a cold air mass and cold weather.

b.
a shift in trade winds in the pacific causes a large mass of warm water to replace cold water, bringing in a warm air mass and warm weather.

c.
water moves from the equator toward great britain and europe, causing warmer temperatures.

d.
the moon and earth line up at a 90° angle, causing large tides and warmer weather.