Answer:
Aim to be at your THR for at least 15 to 20 minutes workout time, and ideally 35 to 45 minutes. If you're a beginner, start at 65 percent to 70 percent of your maximum heart rate and gradually increase the intensity.
Hope this helped...
Your answer is A) - a greenhouse effect
that happens also at large scale, when the atmosphere is playing the role of the windows and the climate on earth became warmer.
Small leaves duh and I know because I study it