Which animal uses its skin for respiration? a. pelican b. lion c. toad d. mackerel

What kind of action is a cause of air pollution

Which would best keep the oxygen cycle stable? a. cutting down jungles to create farmland b. eliminating parks in large cities c. dumping toxic chemicals into the ocean d. reducing the amount of deforestation d. reducing the amount of deforestation

Identify two examples of chemical reactions that you have encountered during the last week. identify an exothermic and endothermic reaction. explain.