Question

multiple choice question when does the embryonic stage begin? it begins once the sperm head penetrates the zona pellucida and fuses with the egg pronucleus it begins at the completion of meiosis ii it begins once implantation has occurred it begins during the third week when cells on the inner face of the blastocyst organize into the inner cell mass

Explanation:

The embryonic stage in human development begins once implantation has occurred. Implantation is a crucial step where the blastocyst attaches to the uterine wall. The first option describes fertilization (not the start of the embryonic stage). Completion of meiosis II is part of oocyte maturation. The inner cell mass formation is an earlier stage (pre - implantation in some aspects compared to the start of the embryonic stage which is marked by implantation).

Answer:

It begins once implantation has occurred