On This Day: 21 January 1960 Little Joe 4 suborbital ---------- test reaches 16 km ?

Questions

Two rats can become the progenitors of 15,000 rats in less than?

Unlike dolphins, porpoises are not very ----------?

The rear portion of the head of a horse is called the ----------?

Unlike most fish, electric eels cannot get enough oxygen from water. Approximately every five minutes, they must surface to breathe, or they will drown. Unlike most fish, they can swim both ----------?

The ring-tailed ----------, a primate found only in Madagascar, meows like a cat.?