Tears produced by emotion differ chemically from tears caused by eye irritation.

Time moves slower in stronger gravitational fields.

Fact #1753 · Science

Rats have demonstrated empathy in laboratory studies.

Fact #1308 · Science

Archaeopteryx is considered a transitional fossil between dinosaurs and birds.

Fact #624 · Science

Time moves slower in stronger gravitational fields.

Fact #1821 · Science

The Earth's tilt is responsible for seasonal climate patterns.

Fact #222 · Science

Certain primates can recognize numerical quantities.

Fact #1327 · Science

The discovery of penicillin by Alexander Fleming revolutionized medicine.

Fact #1187 · Science

Ants do not have lungs and breathe through small openings in their bodies.

Fact #351 · Science