What is an example of a structural plant defense?
tea tree oil produced by the melaleuca tree.
ricin produced by the castor bean plant.
thorns produced by the acacia tree.

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

There are fewer than 100 naturally occurring elements in the universe, but there are millions of different unified substances. explain how this can be true.

How and why organisms are hierarchically classifies