Select the correct answer from the list.(2 points)

Question

Over the past century, the concentration of greenhouse gases in the atmosphere has
been unchanged,
decreased,
increased,
waved up and down,
. This has led to
more,
the same amount of,
less,
heat being held in the troposphere, where infrared radiation is
less,
more,
likely to encounter a greenhouse gas molecule and be
reflected down,
absorbed and re-emitted,
transmitted,

Answer 1

Over the past century, the concentration of greenhouse gases in the atmosphere has increased. This has led to more heat being held in the troposphere, where infrared radiation is more likely to encounter a greenhouse gas molecule and be absorbed and re-emitted.