Under the Highway Traffic Act, children must use a forward-facing child car seat when they weigh between 9 kg and 18 kg (20 to 40 lb.) You need to use a forward-facing child car seat until your child weighs at least 18 kilograms (40 lb.). This is a minimum requirement.
only one sperm can enter an egg (first come first serve) only one egg can be fertilized at a time Answer Actually 2 or more can but the baby won't make it to birth. My daughter died at 16 weeks. I had the baby tested and she had been fertilized by 2 sperms. I agree with this answer.
when an egg and sperm are untied during fertilization, the resulting zygote has 23 pairs of homologous chromosomes, one in each pair from the egg and one from the sperm. Thus the zygote has 46 chromosomes, and when the zygote undergoes mitosis to begin to form an embryo , each cell will have the normal number of 46 chromosomes