Answer:
The most recent common ancestor of all currently living organisms is the last universal ancestor, which lived about 3.9 billion years ago. ... 6,331 groups of genes common to all living animals have been identified; these may have arisen from a single common ancestor that lived 650 million years ago in the Precambrian.
Answer:
the structure by which the embryo is called the oblica cord
B A D C (I think not 100% on this one)
The answer is skeleton.
Please correct me if I'm wrong!! :)
Creationists criticize the idea of natural selection as a circular argument, or tautology, claiming "the fittest are those that survive, and survival is how fitness is defined. "
The definition of natural selection is not tautological because natural selection is measured by contribution to the next generation, not simply survival of an individual organism.
Tautologies or circular arguments are true at all times and therefore are not productive as theories since they cannot be disproved. A tautology is a statement which is true by necessity.
Natural selection is the prevalent theory which explains biological change by predicting the mechanism behind evolution.
Nevertheless, natural selection can be explained non-tautologically. It should be described as the theory which tries to speculate as well as retrodict evolutionary change by environmental forces affecting the organisms.
To learn more about natural selection here
brainly.com/question/9830102
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