The answer is ..b .the smallest units of an element ...
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Genetic mutations increase variety by adding uniqueness to the world. Genetic mutations can come in all shapes and sizes based on the chromosomes in cells. Perhaps someone was born with one blue eye and one green eye, or perhaps they have hair a certain, unusual color. Genetic mutations add variety to the world by making sure everyone isn't the same!!
An example of this would be eye color. You can put contacts in changing the color but not necessarily changing the genes.
The correct answer is B, internal intercostal muscles and abdominal muscles would contract.
Exhalation is the flow of the breath out of the body. During forced exhalation, internal intercostal muscles contracts which lower the rib cage and decrease thoracic volume, while the abdominal muscles push up on the diaphragm which causes the thoracic cavity to contract.