Complete the following sentences.
In females, the uterine wall thickens to receive the __________.

Explanation

To complete the sentence "In females, the uterine wall thickens to receive the __________," we need to understand the process that occurs in the female reproductive system during the menstrual cycle and after fertilization.

1. **Understanding the Uterine Wall**: The uterine wall, also known as the endometrium, undergoes changes throughout the menstrual cycle. It thickens in preparation for a potential pregnancy.

2. **Fertilization Process**: During ovulation, an ovum (egg) is released from the ovaries. If this ovum is fertilized by a sperm (male gamete), it forms a zygote.

3. **Implantation**: After fertilization, the zygote undergoes several divisions and develops into an embryo. This embryo then travels to the uterus and attaches to the thickened endometrium in a process called implantation.

...