The First Vascular Plants Occurred in the Fossil Record _________

question 21

Multiple Choice

The first vascular plants occurred in the fossil record _________ years ago.

• A)430 million
• B)1 million
• C)100,000
• D)4.5 billion

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Definitions:

NADH

Nicotinamide adenine dinucleotide (reduced form), a coenzyme found in all living cells that plays a critical role in energy production through cellular respiration.

Citric Acid Cycle

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate derived from carbohydrates, fats, and proteins into carbon dioxide.

Glucose

serves as a primary source of energy in most organisms, critical for cellular respiration and metabolic processes.

Turn

In a molecular context, a turn refers to a type of secondary structure in proteins where the chain makes a sharp change in direction.