Three characteristics that are unique to mammals include their  ability to feed their babies with milk made in their mammary  glands. Mammals also have hair on their bodies â¦and they have a  single bone that makes up their lower jaw.
buoyancy. n. 1. the ability to float in a liquid or to rise in a fluid. 2. (General Physics) the property of a fluid to exert an upward force (upthrust) on a body that is wholly or partly submerged in it. 3. the ability to recover quickly after setbacks; resilience.
The forces at work in buoyancy. Note that the object is floating because the upward force of buoyancy is equal to the downward force of gravity. In science, buoyancy (pronunciation: /ËbÉÉª.Énsi, -Éntsi/ or /ËbuËjÉnsi, -jÉntsi/;) or upthrust, is an upward force exerted by a fluid that opposes the weight of an immersed object.