Answer:
Chitin is a long-chain polymer derived from glucose. It strengthens cell walls of fungi and the outer covering (exoskeleton) of arthropods (including crabs, shrimps, and insects).
Explanation:
The answer is pyruvate. In the absence of oxygen in
anaerobic respiration, the pyruvate is converted to lactic acid in animals and
ethanol in plants. However, in the presence of oxygen, the pyruvate enters the Krebs
cycle after being converted to Acetyl CoA. Pyruvate is an intermediate product
of glycolysis.
His discoveries on the islands were paramount to the development of his Theory of Evolution by Natural Selection.
On the islands, Charles Darwin discovered several species of finches.
Thanks to his close observations, he discovered that the different species of finches varied from island to island.
Some man-made fibres, too, are derived from naturally occurring polymers. For instance, rayon and acetate, two of the first man-made fibres ever to be produced, are made of the same cellulose polymers that make up cotton, hemp, flax, and the structural fibres of wood.