Explanation

• In the human heart, blood returning from the lungs via the pulmonary veins drains into the left atrium.
• From there, it flows through the mitral valve into the left ventricle, which pumps it out to the rest of the body through the aorta.

Explanation

• Paleontology is the scientific study of fossils and ancient life forms, focusing on the history of life on Earth, evolution, and extinction.
• Paleontologists use fossils to reconstruct the biology, ecology, and behavior of ancient organisms.

Explanation

Thalassemia is a genetic disorder that affects the production of hemoglobin, a protein in red blood cells that carries oxygen to the body's tissues.

It is characterized by abnormal hemoglobin production, leading to anemia, fatigue, and other complications.

Explanation

Leucocytes are also known as white blood cells.

They are colorless, irregularly shaped, nucleated cells that are larger in size compared to red blood cells (RBCs).

They play a vital role in the immune system, helping to fight infections and diseases.

Explanation

Lumen refers to the empty space inside dead cells of xylem vessels, which are arranged vertically and form the vascular tissue in plants.

The lumen provides a pathway for water and mineral transport from roots to leaves.

Explanation

Diastole is the phase of the cardiac cycle where the heart muscle relaxes.

It allowing the chambers to fill with blood.

Explanation

The heartbeat refers to the rhythmic pulsation of the heart that pumps blood throughout the body.

It is a vital function that maintains blood circulation, supplying oxygen and nutrients to tissues and organs.

Explanation

Leukemia is a type of cancer that affects the blood, bone marrow, and lymphatic system.

It occurs when there is an abnormal growth of white blood cells, which can crowd out healthy cells and platelets.

Explanation

Guard cells regulate the opening and closing of stomata, controlling gas exchange and transpiration.

They surround the stomata and change shape in response to environmental conditions, opening or closing the stomata as needed.

Explanation

Root hairs are long, thin, and tubular structures that increase the surface area of the root.

It allowing for a greater rate of absorption of water and minerals from the soil.