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.
An upward force is any force that counteracts the force of gravity. Buoyancy is an example of an upward force because it pushes an object away from the Earth's center of... An upward force is any force that counteracts the force of gravity. Buoyancy is an example of an upward force because it pushes an object away from the Earth's center of mass. Keep Learning.