When Climatic Change Began to Create the Sahara Desert as We

question 31

Multiple Choice

When climatic change began to create the Sahara Desert as we know it today,

• A) farmers moved south into the Niger River valley where they could continue familiar ways.
• B) Saharan herders migrated eastward, where they found lands conducive to their way of life.
• C) many of the pastoral herders became nomadic, using the scant resources of the desert to eke out a living.
• D) agriculture spread south into the rain forests, where cereals began to be grown for the first time.
• E) the cultivation of millet and rice was carried into both the Niger and Nile River valleys by those forced to migrate.

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Definitions:

Lignin

An organic substance binding the cells, fibers, and vessels of wood and plants, contributing to the stiffness and strength of the cell wall.

Polymer

Large molecules composed of many repeated subunits, known for their broad range of properties and uses in natural and synthetic materials.

Amino Acids

Organic compounds that combine to form proteins, serving as the building blocks of life with crucial roles in cell function and metabolism.

Primary Growth

Growth that occurs as a result of cell division at the tips of stems and roots, causing them to elongate, and gives rise to primary tissues.