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Sorry, but this question is impossible to answer without any background information. Hope this helped :)
The cellular respiration processes of all living cells make use of the coenzyme Nicotinamide adenine dinucleotide (NAD). It plays a key role in energy metabolism by accepting and donating electrons. The low energy form NAD+ shown at left is raised to the high energy form NADH.
Insects are not vertebrates, they’re invertebrates