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.

The answer is; D

Solar cells usually convert solar energy into electricity which could later be reserved. The efficiency of solar cells is still low, compared to other sources, with a conversion rate of 15% - 22%. This reduces the attractiveness of solar cells as a competitive source of energy. This also makes this form of energy expensive due to its inefficiency.

i have to report this, it doesn't relate to biology

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.