Compared to oil and gas, solar energy:

costs less to produce

costs more to produce

is always available

does not require any machinery

in theory, limestone is composed principally of the compound calcium carbonate - caco3, but in reality this compound is deposited in conditions involving a number of other compounds as impurities so it ends up being a mixture of many compounds.

hope this : -)

tony (lordcaos066)

i think it is d. e because the next one is igneous.