1) Bats are the only mammals capable of sustained flight.

2) A newborn kangaroo is about 1 inch (2.5 centimeters) long and weighs less than a gram.

3) The concept of proportional representation, used in some electoral systems, aims to ensure that political parties' representation in government aligns more closely with the proportion of votes they receive from the electorate.

4) Male seahorses are the ones who give birth to their offspring.