Human Embryos and Fish Embryos Share a Number of Features

question 35

Multiple Choice

Human embryos and fish embryos share a number of features.Why?

• A) Humans and fishes share a common ancestor.
• B) All embryos share a similar environment and have acquired similar features via directional selection.
• C) Mutations in human and fish embryos have caused them to look alike.
• D) Humans and all other vertebrates, including fishes, have identical sets of genes; the differences between the various species are caused by the patterns and timing of gene activation.

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Definitions:

Variable

1. In symbolic logic, a symbol that stands for some, but any, unnamed individual thing; 2. In statistics, a trait regarded as a generic attribute that can exist in different degrees (values).

Closed Sentence

In predicate logic, a statement in which every variable is bound by a quantifier.

Variable

An element, feature, or factor that is liable to vary or change, often used in mathematics, statistics, and scientific experiments to represent quantities or qualities that can assume different values.

Open Sentence

A mathematical or logical statement containing one or more variables that does not have a definitive truth value until the variables are specified.