Question

Meroblastic cleavage refers to which type of division of egg?
A. Complete
B. Spiral
C. Incomplete
D. Horizontal

Answer 1

In developmental biology cleavage is a division of cells in the early embryo . The process follows fertilization with the transfer being triggered by the activation of a cyclin-dependent kinase complex.

Step by step answer: The zygote of many species undergoes rapid cell division with no significant overall growth producing a cluster of cells with the same size as the original zygote. The different cells derived from cleavage are called blastomeres and form a more compact mass called the morula. Cleavage ends with the formation of the blastula. Depending mostly on the amount of yolk in the egg, the cleavage can be divided into two types which are holoblastic in which total or entire cleavage occurs and meroblastic in which partial or incomplete cleavage occurs. Meroblastic cleavage is common in birds.
So, the correct answer is C
Some additional information:
In holoblastic cleavage, the zygote and blastomeres are completely divided during the cleavage so the number of blastomeres doubles with each cleavage. Holoblastic cleavage is of many types Such as bilateral holoblastic radial holoblastic rotational holoblastic and spiral holoblastic cleavage. Meroblastic cleavage is in the presence of a large amount of yolk in the fertilized egg cell the cell can undergo partial or meroblastic cleavage. Two major types are of plastic cleavage discoidal and superficial. In discoidal cleavage, the cleavage furrows do not penetrate the yolk. In superficial cleavage, mitosis occurs but not cytokinesis resulting in a polynuclear cell with the yolk positioned in the center of the egg cell.

Note: Discoidal cleavage is commonly found in birds, reptiles, and fishes that have the egg cell with the yolk concentrated at one end.