Question

because they are both lean, when mark and lauren have children, they will most likely have children who are lean.

Answer 1

that statement is true. A fetus absorb the food that exist within the parent's body. The more mass the mother has, the more food will be available for the fetus. If the mother is lean, it will be most likely that the fetus will be lean because it has a sufficient food resource.

Answer 2

We are given a scenario wherein both parents (mother and father) are lean. The possibility of them also having lean children will be very high. This is because the genetic materials which causes the parents to be lean will be passed on the offsprings.