In space, are fires possible without oxygen? If so how would it happen?

How do hydroponic plants differ from nonhydroponic plants? a.) hydroponic plants can grow in a dryer soil. nonhydroponic plants grow in moist soil. b.) hydroponic plants grow on other plants and are known as air plants. nonhydroponic plants do not grow on other plants. c.) hydroponic plants can only grow in rain forests. nonhydroponic plants cannot grow in rain forests. d.) hydroponic plants are grown without soil. nonhydroponic plants are grown in soil.

An ionic compound can conduct electricity when a it is dissolved in water b its crystals are ground into powder c it is in solid form d it is heated to just below its melting point

What kind of simple machine is a catapult?