Question

what are the three Mechanical and Barrier methods to control population?​

Answer 1

These mechanical barriers include diaphragms, caps and sponges, early versions of which are shown in Figure 4c. These all fit tightly over the cervix, and caps and diaphragms come in different sizes to accommodate women of different shapes.

Answer 2

Barrier Methods of Birth Control: Spermicide, Condom, Sponge, Diaphragm, and Cervical Cap.

By this
Condoms protect against pregnancy.
...
Barrier methods are safe to use while breastfeeding.

Barrier methods do not use hormones. ...

These methods do not affect a woman's menstrual cycle. ...