The Direction of Shell Coiling in Snails Such as Limnea

question 18

Multiple Choice

The direction of shell coiling in snails such as Limnea peregra is determined by the egg's genotype,which affects orientation of the spindle in early cleavage divisions.How could the egg genotype cause the directional orientation of a spindle in the embryo?

• A)by products of mitochondrial genes that pull the centrioles toward the mitochondrial position
• B)by attachment of spindle fibers to mitochondria at the edges of the cell
• C)by maternally directed placement of mRNAs and proteins at appropriate positions in the egg cytoplasm
• D)by the release of maternal mitochondrial genomes into the egg cytoplasm
• E)by zygotic gene activation due to maternal mitochondrial genes

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Definitions:

Atlantic Trade Routes

The sea lanes and passages across the Atlantic Ocean used for the exchange of goods and slaves between the Americas, Europe, and Africa.

Plantation Economy

An economic system heavily based on agricultural production, often on a large scale, specializing in cash crops, and reliant on the labor of enslaved or indentured workers.

Colonization

The action or process of settling among and establishing control over the indigenous people of an area, often leading to the exploitation and cultural assimilation of those people.