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.
Background Information. Fertilization of an egg by a sperm occurs soon after its release from the ovary (ovulation) into the fallopian tube to form a single cell embryo (zygote) containing the genetic material of the sperm and egg. The zygote then divides progressively into a multi-cell embryo. When the embryo contains about 12-16 cells, it is called a morula. After 5-6 days, the embryo contains many cells and forms a cystic cavity termed the blastocoel within its center. At this stage, the embryo is called a blastocyst and has undergone the 1st step in differentiation; it separates into two tissue types, the trophectoderm and the inner cell mass.