I need help ‍ or else I'm gonna fail

Which of the activities listed below could limit global warming by slowing the increase in atmospheric carbon dioxide levels? view available hint(s) select all that apply. a. replacing fossil fuels with nuclear energy b. burning vegetation to clear land for agriculture c. limiting soil erosion so organic matter takes longer to decompose d. choosing a fuel-efficient car, or bicycling to school or work e. using more electrical appliances and cars f. cutting down forests to build houses

What is the approximate circumference of the circle shown below? 12.2 cm

How would i answer this for an exam?