Choose the best answer.

Conjunctivitis caused by the common cold is very                  and can spread rapidly between people.

Choose A, B, C, or D that best completes each sentence.

All of the disasters resulted from_______ will continue to have a devastating effect on socio-economic development.

Choose A, B, C, or D that best completes each sentence.

Most climate scientists agree the main cause of the current global warming trend is human expansion of the greenhouse _______.

Choose the best answer.

A strong greenhouse effect will warm the oceans and partially melt glaciers, increasing ______.

Choose A, B, C, or D that best completes each sentence.

Certain _______  in the atmosphere, such as carbon dioxide, methane and nitrous oxide, block heat from escaping.

Choose A, B, C, or D that best completes each sentence.

Methane is a far more active _______ than carbon dioxide, but also one which is much less abundant in the atmosphere.

Choose the best answer.

Greenpeace works to promote public                of the dangers that threaten our planet today.

Choose A, B, C, or D that best completes each sentence.

The low _______ in the Mekong Delta leads to acute saline intrusion much deeper than the traditional 30 to 40km of mainland that is contaminated with saltwater.