DNA contains the genetic material and comes from both the parents
If the ratio is 9:2 that means that 45 would by ñ times 9. At the same time, ñ must also fit the ratio. Using this knowledge, you can divide 45 by 9, giving you 5, then multiply it by 2. This means that the child is 10 years old.
Argyroneta aquatica because it is the only species of spider that lives entirely uder water