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Multiple Choice
The zygotes of many protostomes undergo __________ cleavage and __________ cleavage.
A
spiral; radial
B
spiral; indeterminate
C
radial; indeterminate
D
radial; determinate
E
spiral; determinate
Verified step by step guidance
1
Understand the terms: In embryonic development, 'cleavage' refers to the series of cell divisions that occur immediately after fertilization. 'Spiral cleavage' is a type of embryonic development in which the planes of cell division are diagonal to the vertical axis of the embryo, resulting in a spiral arrangement of cells.
Learn about 'determinate cleavage': In determinate cleavage, the fate of each embryonic cell is determined early in development. This means that if a cell is removed from the embryo, it cannot develop into a complete organism on its own.
Identify the characteristics of protostomes: Protostomes are a group of animals that include mollusks, annelids, and arthropods. They typically exhibit spiral and determinate cleavage during early embryonic development.
Differentiate between spiral and radial cleavage: Spiral cleavage is characteristic of protostomes, while radial cleavage, where cells are aligned directly above one another, is typical of deuterostomes.
Conclude that the zygotes of many protostomes undergo spiral cleavage and determinate cleavage, as these are defining features of their embryonic development.