What Geologic Events Are Expressed in This Cross Section of the Western

question 34

Multiple Choice

What geologic events are expressed in this cross section of the western U.S. in late Paleozoic - early Mesozoic time?

• A) an old episode of continental rifting that lead to a passive margin
• B) collision of an island arc with western North America
• C) oceanic crust and sediment that was thrust onto North America
• D) a basin formed by the weight of thrust sheets
• E) all of these

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Definitions:

Mesoderm

The middle layer of an embryo in early development, between the endoderm and ectoderm, which gives rise to muscles, bones, and blood tissues.

Germ Layer

Each of the three layers of cells (ectoderm, mesoderm, and endoderm) that form during embryogenesis, which give rise to all tissues and organs of an organism.

Radial Cleavage

A type of embryonic development in which the cells divide parallel or perpendicular to the polar axis, resulting in a radially symmetrical embryo.

Echinoderms

A phylum of marine animals characterized by radial symmetry and a unique water vascular system, including starfish and sea urchins.