Questions: The germinal period begins with implantation begins at fertilization and ends with implantation

The answer is the last one: begins at fertilization and ends with implantation.

Explanation for each option:

1. Begins with fetal weight gain: This is incorrect. Fetal weight gain occurs much later in the pregnancy, during the fetal period, not the germinal period.

2. Begins with implantation: This is incorrect. The germinal period ends with implantation, not begins with it.

3. Is the time it takes to germinate your answer to this question: This is incorrect and seems to be a humorous or misleading option.

4. Begins at fertilization and ends with implantation: This is correct. The germinal period starts at fertilization when the sperm and egg combine to form a zygote and ends when the zygote implants itself into the uterine wall.

Summary: The germinal period begins at fertilization and ends with implantation.