There is no safe day.
The menstrual cycle refers to the reproductive cycle, a woman [of reproductive age, and if not using hormonal birth control] is experiencing her menstrual cycle every day. It's safe to be sexually active at any time as long as you are old enough to be sexually active, practicing safer sex, and using birth control to prevent unintended pregnancy.
During a typical 28 day cycle a woman will be fertile around days 7-16, and all other days would be considered safe days. However unless you use fertility awareness method you can't know for sure when you are fertile or not as cycles change.
The menstrual cycle starts with menstruation. The firswt day of your menstrual cycle is considered to be the first day of true bleeding during your menstrual phase.
The Reason for a cycle of day and night is all based on the rotation of the earth. During the day, the part of the earth where you are located is facing the sun, and during the night, the part of the earth where you are located is facing away from the sun.
Yes, (see related link below)
Because it requires light
each day at noon
I believe that you mean your fertile period, this means the time during your menstrual cycle that you are able to get pregnant. During a typical 28 day cycle a woman would be fertile from day 7-16.
On day 14 of the menstrual cycle, the egg is typically released from the ovary in a process called ovulation. If the egg is fertilized by sperm, it can result in pregnancy. If not fertilized, the egg will disintegrate and be shed along with the uterine lining during menstruation.
Most women ovulate between day 12 and day 18 of their cycle.
The first day of your menstrual cycle is the first day of your period. You onlystart counting on the first day you see true bleeding, don't count from when you start spotting.