The Most Important Event During the Cambrian Period Was the

question 92

Multiple Choice

The most important event during the Cambrian period was the

• A)emergence of the fishes.
• B)ability of organisms to form an outer skeleton.
• C)emergence of the trilobite.
• D)ability of organisms to develop lungs.

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Definitions:

Thrifty Genotype Hypothesis

The thrifty genotype hypothesis proposes that alleles that were advantageous in the past (for example, because they were “thrifty” and stored nutrients well) may have become detrimental in the modern world, contributing to metabolic syndrome, obesity, and type 2 diabetes.

Antagonistic Pleiotropy

A hypothesis suggesting that a single gene can affect multiple traits in a way that is beneficial in some aspects but detrimental in others.

Hygiene Hypothesis

Suggests that a lack of early childhood exposure to infectious agents, symbiotic microorganisms, and parasites increases susceptibility to allergic diseases by suppressing the natural development of the immune system.

Alleles

Different versions of a gene that determine distinct traits that can be passed on to offspring.