D genetic drift
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Answer:
Non contact forces
Explanation:
non-contact force is a force which acts on an object without coming physically in contact with it. The most familiar non-contact force is gravity, which confers weight. In contrast a contact force is a force applied to a body by another body that is in contact with it.
Shivering is the primary human response in a cold environment. It helps because rapid movement of your muscles increases the body temperature.