Level 4 unit3 4/4 vocabulary

Civil war is fought between the citizens of the same country and is fought within the country. If the citizens disagree about a policy or leader, they may fight a civil war.
A world war is fought when countries form alliance and these alliances fight each other. A world war involves many or most of the world’s powerful countries. There were two world wars in the 20th century. Terrorism involves groups of individuals rather than countries. Terrorists may come from different countries, and they may share the same beliefs. Terrorists often use car bombings and suicide attacks on innocent people. A terrorist’s attack can happen at any time in any place.
An invasion occurs when one country attacks another. It sends its army into another country and attempts to take control. One of the famous invasions was when France invaded Russia in 1812.
A defense war occurs when a country is attacked and it needs to defense itself. Most countries have a military so that it can defense itself when it’s attacked.
When France invaded Russia in 1812, the Russian army fought a defense war and defeated the French army.
A cell is a basic unit of life. A cell is the smallest structure that can live and reproduce. Cells grow in develop, reproduce and interact with environment.
Photosynthesis is one of the most important biological processes. It allows plants capture and use light as an energy source. Photosynthesis is the process of converting light energy into chemical energy.
A virus is a small biological structure that attack and enter cells. Once inside a cell, a virus reproduces and makes many copies of itself. Some diseases such as influenza are viruses.
Bacteria are one-cell forms of life that all around us. Although they have a single cell structure, they are very important. Many bacteria are inside us and help us to digest our food. DNA is complex mole cure that stores information and can make copies of itself. Nearly every cell in a person’s body has the same DNA. The information stored in DNA tells cells what to do and it’s necessary to reproduction.