In which type of child safety device should a child who is 2 years old sit?

Common theory questions

Children should sit in a backward-facing child seat from 7 months up to about 4 years.

A child seat must never be placed in a seat with frontal airbag protection.
If the child's head clears the edge of the child seat, the seat is too small.
Secure the child with the child seat's harness. The lap belt should sit over the hip and not over the stomach.
Secure the child seat with a car's seat belt or an ISOFIX attachment system.
In the front seat, the child seat should rest against the dashboard.
In the back seat, the child seat should rest against the back of the front seat.

There are also front-facing child seats, but they have a significantly lower protective capacity than backward-facing child seats.