There are many different kinds of sewage treatment plants which vary in the process by which they treat wastewater. Generally, they can be classified into the following types of system: 1  Activated sludge plant (ASP). 2  Rotating disc system. 3  Submerged aerated filter (SAF). 4  Suspended Media Filters (SMF).
In certain species of sea life, male pregnancy is common. The male incubates and births live young instead of the female. Human males are not able to do so, and medical risks of a male pregnancy are extreme. Transgender individuals can become pregnant if reproductive organs are left intact. A common phenomenon is a sympathetic pregnancy, where a man exhibits all the symptoms of pregnancy along with his expectant partner.
Condoms are a barrier method of contraception. There are male condoms and female condoms: A male condom is a thin sheath (usually made of latex, a type of rubber) that is worn on the penis. A female condom is a polyurethane sheath with a flexible ring at either end. One end is closed and inserted into the vagina; the other end is open and the ring sits outside the opening of the vagina.