The first organisms on earth appeared approximately 3.5 billion years ago and were all unicellular. multicellular organisms have only existed for about one billion years. what evolutionary milestone made it possible for more complex, multicellular organisms to exist?

What are tissues? a groups of tissues that work together b basic units of structure and function c groups of cells that perform the same function d multiple organs that perform a major function

Were does condensation occur? a) hydroshereb) lithosherec) boishered) atmosphere

Which set of characteristics best describes sedimentary rock? a) largest type of rock, made of organic matter, hardest type of rock b) often contains layers, forms near sources of water, contains fossils c) least abundant type of rock, made of other rocks, made mostly of minerals d) most abundant type in earth's crust, made of magma/lava, contains no fossils