Which shows the need for gene banks for agricultural crops? plagues wiped out the entire crop in a large region. global warming caused reduced rainfall in an agricultural area. volcanic eruptions formed new land. soil erosion increased due to poor farming practices.

Plagues wiped out the entire crop in a large region.

Explanation:

Gene banks are the places which preserves the genetic materials of the living beings so that they can control the limiting population of the organisms, and they can be used for the purpose of experimentation.

The gene banks preserves the seeds, tissues, pollen, genes in them at controlled conditions.

According to the given situation, the gene bank will be useful in cases when the complete crop has been destroyed by fire, natural calamity or insect or microbial infestation. The remaining unaffected materials can be used for the growth and harvest of the new crops.

Hence, Plagues wiped out the entire crop in a large region. can be a correct option.

answer: a) a compound microscope has a greater magnification ability than a simple microscope.

explanation: