**Life on Earth is thought to have begun?
a..540 million years ago, at beginning of Paleozoic era
b..700 million years ago, during Precambrian
c..2.7 billion years ago, when oxygen began to accumulate in atmosphere
d..b/w 3.5 to 4.0 billion years ago
e..4.5 billion years ago, when Earth formed
**Stromatolites are..
a..early prokaryotic fossils found in sediments around hydrothermal vents
b..protobiont that forms when lipids assemble into bilayer surrounding organic molecules
c..members of kingdom Protista that are both motile and photosynthetic
d..fossils appearing to be eukaryotes that are about twice the size of bacteria
e..layered communities of bacteria, fossils of which represent oldest known prokaryotes
**Liposomes are..
a..spontaneously forming droplets surrounded by a lipid membrane
b..prokaryotes that lived as endosymbionts in larger prokaryotic cells
c..polypeptides formed in laboratory by dripping organic monomers onto hot rocks
d..abiolotically produced lipids
e..RNA self-replication molecules
HELP ME ANSWER THESE 3 IMPORTANT QUESTIONS.~