Oxygen (o2) and nitrogen (n2) do not have much greenhouse effect, but several trace gases including carbon dioxide (co2), methane (ch4), nitrous oxide (n2o), and various chlorofluorocarbons are important greenhouse gases. the primary mechanism by which these greenhouse gases warm the earth is: a. preventing convection currents that take heat aloft, in the same way that the glass of a greenhouse stops convection currents and so makes the air in the greenhouse warmer. b.raising the atmospheric pressure, because squeezing air warms it, as we saw at the redwoods. c.experiencing chemical reactions with each other, which release energy. d.absorbing some of the infrared radiation emitted from the earth. e.making politicians mad, so they give speeches that heat the air.

Imagine that a new planet is discovered with two moons of equal mass: moon a and moon b. the mass of the new planet is greater than the combined mass of its moons. moon a is farther away from the new planet than moon b. what is the planet's gravitational pull on moon a compared to the planet's gravitational pull on moon b? the planet's gravity repels moon a with a greater force than it repels moon b, which is why moon a is farther away. the gravitational pull on moon b is greater than on moon a because moon b is closer to the new planet than moon a. the gravitational pull on moon b is greater than on moon a because moon b is farther away from the new planet than moon a. the gravitational pull on moon a is the same as the gravitational pull on moon b because distance does not affect the planet's gravity.