01. blood

Posted: July 2026 23 Blood is a liquid tissue that carries oxygen, nutrients, and waste throughout the body. The average person has about 4–6 liters of blood, which is made of red blood cells, white blood cells, platelets, and plasma. Red blood cells carry oxygen, white blood cells fight germs, and platelets help stop bleeding. Blood gets its red color from hemoglobin, a protein that contains iron.

02. blood

Posted: July 2026 24 Blood travels through the body using a network of blood vessels called arteries, veins, and capillaries. Your heart pumps blood about 100,000 times every day. Red blood cells live for around 120 days before being replaced. Your body creates millions of new blood cells every second. Blood also helps control body temperature and protects you from harmful germs.

03. blood

Posted: July 2026 25 Blood makes up about 7–8% of your body weight. There are different blood types, including A, B, AB, and O. O-negative blood can be given to many people during emergencies. Blood helps heal wounds by forming clots. The plasma in blood carries proteins, hormones, and nutrients to different parts of the body.

04. cells

Posted: July 2026 26 Human cells have different jobs that help the body function. Some cells carry oxygen, some fight infections, and others help create energy. Each type of cell has a special role in the body.

05. cells

Posted: July 2026 27 Nerve cells, also called neurons, send messages throughout the body. They help control movement, thoughts, feelings, and reactions. Some neurons can send signals very quickly

06. cells

Posted: July 2026 28 Plant cells and animal cells are different in some ways. Plant cells have a cell wall and chloroplasts, while animal cells do not. Both types of cells contain DNA and need energy to survive.

07.cells

posted: july 2026 29