Large lumps that appear on the legs at night could be a sign of a circulatory problem. It is best to get this condition checked out by a physician.
Bell's Palsy - a form of paralysis affecting a nerve that controls facial muscles.
Birds can appear to be flying in place due to strong winds or air currents that allow them to hover without moving forward.
Adalia Rose has a condition called Progeria. It is an extremely rare condition that causes rapid physical ageing in children. Those with the condition rarely live past the age of 13. See the related link below for more information.
Thermal energy, or heat energy, causes molecules to move around quickly. As molecules absorb more thermal energy, they gain kinetic energy and their movement increases, leading to higher temperatures.
Natural selection is a process that causes an organism's poorly suited characteristics to disappear over time. Organisms with traits better suited to their environment are more likely to survive, reproduce, and pass on their advantageous traits to their offspring, while those with less favorable characteristics are less likely to survive and reproduce.
A catalyst
Evaporation.
Evaporation
Sudden blood flow (if running quickly, for example), allergies / hives, being cold, getting cold / warming up too quickly, circulation problems.
The rotation of the earth is what causes the sun to appear to set
Tiny white bumps on the face can be a condition called milia. These bumps can appear at age. There are harmless.
A black dot on a cat's nose is typically caused by a benign condition called lentigo simplex, which is a harmless increase in pigmentation.
A condition which causes part of the brain not to form is called anencephaly.
Forest Whitaker's scalp may appear discolored due to a condition such as vitiligo, a skin disorder that causes loss of skin color in patches. It is a harmless condition that affects the melanin production in the skin.
Erosion by both wind and water.
Francium is very unstable and easily disappear.
I don't know about the bruise part of the description, however in the condition Rheumatoid arthritis there are what is known as a nodule these are hard and can be painful They don't take long to appear and can disappear again over time. If they are rheumatic nodules it is wise to get it looked at as uncontrolled rheumatoid arthritis can lead to serious joint damage over a short period of time.