Each of the First Three Cambrian Mass Extinctions of Trilobites

question 3

Multiple Choice

Each of the first three Cambrian mass extinctions of trilobites was probably due to

• A) gradual climatic cooling.
• B) sudden climatic warming.
• C) sudden climatic cooling.
• D) gradual climatic warming.

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Definitions:

Myofilaments

The filamentous components of muscles, comprising mainly of actin (thin filaments) and myosin (thick filaments), essential for muscle contraction.

Sarcoplasmic Reticulum

A specialized type of smooth endoplasmic reticulum found in muscle fibers, critical in regulating calcium ions and thus muscle contraction.

T-tubules

Tubular extensions of the cell membrane in muscle cells, transmitting electrical signals from the surface to the interior of the muscle fiber.

Femoris

Refers to muscles located in the thigh, typically pertaining to parts of the quadriceps, such as the quadratus femoris or biceps femoris.