Question

multiple choice question
what is a morula?
the stage in development in which the germ layers form
the enzyme containing \cap\ on the head of the sperm
a preembryo which is a solid ball of cells
the barrier layer of the egg formed after the penetration of the sperm

Explanation:

A morula is an early stage of embryonic development. It occurs after a fertilized egg (zygote) undergoes several rounds of cell division (cleavage). The cells, called blastomeres, are tightly packed together, forming a solid ball - like structure. This is the pre - embryo stage before the formation of a blastocyst (which has a fluid - filled cavity).

• The stage in development in which the germ layers form is gastrulation, not the morula stage.
• The enzyme - containing "cap" on the head of the sperm is the acrosome.
• The barrier layer of the egg formed after the penetration of the sperm is the fertilization membrane (or zona pellucida modifications in some cases), not the morula.

Answer:

A preembryo which is a solid ball of cells.