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.
Fertilization of the egg by the sperm restores the diploid number of 46 chromosomes. We have 46 chromosomes that, if you lined them up by size and shape (karyotyped them), are actually 23 pairs of chromosomes - one was originally from mom and the other from dear 'ol dad.