The Hox Genes Came to Regulate Each of the Following

question 20

Multiple Choice

The Hox genes came to regulate each of the following in what sequence, from earliest to most recent?
1) identity and position of paired appendages in protostome embryos
2) anterior-posterior orientation of segments in protostome embryos
3) positioning of tentacles in cnidarians
4) anterior-posterior orientation in vertebrate embryos

• A) 4 → 1 → 3 → 2
• B) 4 → 2 → 3 → 1
• C) 4 → 2 → 1 → 3
• D) 3 → 2 → 1 → 4
• E) 3 → 4 → 1 → 2

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Definitions:

Mammals

Warm-blooded vertebrates characterized by the presence of hair or fur, the secretion of milk by females for feeding their young, and (typically) the birth of live young.

Nerve Net

A simple form of neural organization found in cnidarians and ctenophores, featuring a diffuse network of interconnected nerve cells.

Evolution

The process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.

Nervous Systems

The network of nerve cells and fibers transmitting signals between different parts of the body, comprising the central and peripheral nervous systems.