But the constituents were themselves derived from complex substances almost equally difficult to synthesize.

When they die, after a year or so, they leave more complex substances behind.

Myelin, from which the white matter of the brain takes its colour, is a complex substance made up of at least ten different chemicals.

It is a complex substance and there is still much to be learned about it.

All living plants and animals organize their foods into complex highly organized biochemical substances.

Water is a very complex substance and its unique properties are essential for life.

In a synthesis reaction, two or more simple substances combine to form a more complex substance.

Which means, simply, that with complex substances like wine, critical judgments depend more on smell than taste.

This work, more than any other, convinced organic chemists that the synthesis of any complex substance was possible, given enough time and planning.

Although ice cream can be easy to make at home, it is actually a very complex substance.