Question

which of the following can be done to prevent global warming?
cut down trees.
use foam fire extinguishers.
use halon fire extinguishers.
do not recycle old cfcs.

Explanation:

Cutting down trees reduces carbon - sequestering capacity, and using certain fire - extinguishers and not recycling CFCs contribute to harmful emissions. None of the other options are beneficial for preventing global warming.

Answer:

None of the above.