Explanation:

To understand how many ova are produced by a 35-year-old woman having 3 children, we need to understand the female reproductive system and the ovulation process.

Female Reproductive System:
The female reproductive system consists of ovaries, fallopian tubes, uterus, cervix, and vagina. The ovaries are the primary reproductive organs that produce and release ova (eggs) into the fallopian tubes.

Ovulation Process:
Ovulation is the process of releasing a mature egg from the ovary into the fallopian tube. This process occurs once a month in a typical menstrual cycle. The egg is released from the ovary and travels through the fallopian tube, where it may be fertilized by sperm. If the egg is not fertilized, it is absorbed by the body and expelled during menstruation.

Relation between childbirth and ovulation:
During pregnancy, ovulation stops, and a woman does not release any eggs until after childbirth. After childbirth, a woman may start ovulating again, usually within a few months.

Answer:
Based on the above information, we can conclude that a 35-year-old woman who has had 3 children has ovulated 3 times. Each ovulation results in the release of one egg, so she has produced 3 eggs in total.

Therefore, the answer is 3.