Why do i feel dizzy and feel like i'm going to pass out?

Mary is 14 year old her resting heart rate is 70 beats per minute. calculate 50% of mary's maximum heart rate to fine her target heart rate

First to answer will be the brainliest i need the answer asap

Send sperm live for about 48 hours after ejaculation and ovum for only 24 hours after ovulation intercourse can occur after ovulation for fertilization to occur