Before solar energy can become a competitive form of energy available for consumers, which of the following events must occur? a. solar energy is used to power a photovoltaic cell, which splits water into hydrogen and oxygen, and the hydrogen can be used to provide energy. b. solar energy passes through a photovoltaic cell, which then stores the energy as heat until it is needed. c. energy must be converted into another form, stored until needed, and then converted into heat. d. energy must be collected, converted into another form, and stored until needed.

Refer to this portion of a dichotomous key for fish identification to answer the question. 1. (a) has a single dorsal fin ® 5 (b) has a double dorsal fin ® 2 2. (a) one fin is spiny, the other is smooth ® 3 (b) one fin is not spiny or smooth ® 4 5. (a) has small fin on back near tail ® 6 (b) has no fin on back near tail ® 7 6. (a) has barbs near the mouth ® catfish (b) does not have barbs near the mouth ® 10 7. (a) tail is asymmetrical ® 8 (b) tail is symmetrical ® 9 10. (a) scales are small ® trout (b) scales are large ® whitefish what is the next step to complete to identify a fish that has a single dorsal fin, no fin on the back near the tail, and no barbs near the mouth? step 2 step 5 step 7 step 10