Organic molecules are sometimes found within meteorites that crash into earth. which meteorite condition in space is similar to what most likely was present on early earth?
abundance of oxygen
very cold temperatures
presence of inorganic molecules
low levels of ultraviolet radiation

The early earth had all the three conditions except abundance of oxygen. The  atmosphere of the early earth was same as that of the condition present in space. The organic molecules found in the meteorites might have originated from the inorganic substance that is present in the space that was present in meteorite. The early earth had very low amount of oxygen and very cold temperature, presence of inorganic molecules and low levels of ultraviolet radiation.

the most common type of reef is the fringing reef. this type of reef grows seaward directly from the shore. they form borders along the shoreline and surrounding islands.