The history of mathematics stretches back thousands of years to ancient civilizations.
Babylonian mathematicians developed sophisticated techniques for solving quadratic equations
around 2000 BCE, long before formal algebra was established. Egyptian mathematicians used
geometric methods to survey land and construct the famous pyramids. Greek philosophers
including Pythagoras, Euclid, and Archimedes laid the foundations for geometry and number
theory that still underpin modern mathematics.

The development of calculus in the seventeenth century by Isaac Newton and Gottfried Wilhelm
Leibniz independently represents one of the most significant advances in mathematical history.
Calculus provided tools for describing motion, change, and continuous phenomena, enabling
breakthroughs in physics, engineering, and economics. The notation introduced by Leibniz
became the standard used throughout the world today.

Biology is the scientific study of living organisms and their interactions with the environment.
Cellular biology examines the structure and function of the cell, the fundamental unit of life.
All living things are composed of cells, from the simplest bacteria to complex multicellular
organisms such as plants, animals, and fungi. The discovery of DNA structure by Watson and
Crick in 1953, building on X-ray crystallography work by Rosalind Franklin, revealed the
molecular basis of heredity and opened the era of molecular biology.

Photosynthesis is the process by which plants, algae, and some bacteria convert sunlight into
chemical energy stored as glucose. The chlorophyll molecules within chloroplasts absorb light
primarily in the red and blue wavelengths, reflecting green light back to our eyes. Carbon
dioxide absorbed from the atmosphere and water drawn up from the roots combine through a
series of biochemical reactions to produce sugars that fuel the entire ecosystem.

The Earth formed approximately four and a half billion years ago from a cloud of gas and dust
surrounding the young Sun. Early Earth was a violent place, bombarded by meteorites and
wracked by volcanic activity. Gradually the crust cooled and solidified, oceans formed from
water delivered by comets and released from volcanic vents, and simple chemical compounds
assembled into the first self-replicating molecules that would eventually become life.

Plate tectonics describes the movement of large segments of the Earth's crust over the
partially molten mantle below. The continents that seem so permanent to us drift slowly,
colliding to form mountain ranges and rifting apart to create new ocean basins. The Himalayan
mountains arose from the collision of the Indian subcontinent with the Eurasian plate, a
process that began around fifty million years ago and continues today, pushing the peaks
higher by a few millimeters each year.

The atmosphere of Earth consists primarily of nitrogen and oxygen, with trace amounts of
argon, carbon dioxide, and water vapor. The stratospheric ozone layer absorbs ultraviolet
radiation from the Sun that would otherwise damage living organisms at the surface. Human
industrial activity has released chlorofluorocarbons and other compounds that deplete ozone,
leading to a thinning of this protective shield over the polar regions.

Ancient Rome dominated the Mediterranean world for centuries, building an empire that
stretched from the British Isles to Mesopotamia. Roman engineers constructed roads, aqueducts,
and public buildings that remain impressive feats even by modern standards. The Latin language
spread throughout the empire and evolved into the Romance languages including Italian, French,
Spanish, Portuguese, and Romanian. Roman law, adapted and refined over centuries, forms the
basis of legal systems in much of Europe and Latin America.

The Renaissance, meaning rebirth, was a cultural movement that emerged in Italy during the
fourteenth century and spread across Europe over the following two centuries. Artists and
scholars rediscovered classical Greek and Roman texts preserved in Byzantine and Islamic
libraries. Leonardo da Vinci exemplified the Renaissance ideal of the polymath, excelling in
painting, sculpture, architecture, engineering, anatomy, and natural philosophy.

Astronomy studies the universe beyond Earth, encompassing stars, galaxies, planets, and the
large-scale structure of space and time. The invention of the telescope in the early seventeenth
century transformed observational astronomy, allowing Galileo to discover the moons of Jupiter
and the phases of Venus. Modern telescopes orbiting above the atmosphere capture light across
the entire electromagnetic spectrum, from radio waves to gamma rays, revealing phenomena
invisible to ground-based observers.
