Investopedia / Mira Norian An economic cycle is the overall state of the economy as it goes through four stages: expansion, peak, contraction, and trough. An economic cycle, also known as a ...

Nitrogen is one of the primary nutrients critical for the survival of all living organisms. Although nitrogen is very abundant in the atmosphere, it is largely inaccessible in this form to most ...

The menstrual cycle has four phases: menstrual, follicular, ovulation, and luteal. The main purpose of the menstrual cycle is to produce an egg for potential fertilization by sperm. Stress ...