Explanation

• Platelets, also called thrombocytes.
• They are blood cells that play a vital role in blood clotting.
• When a blood vessel is injured, platelets aggregate to form a plug that stops the bleeding.

Explanation

The melting point of ice at normal atmospheric pressure is 0 °C (zero degrees Celsius).

Key Points:

• 0 K (zero Kelvin) is equivalent to -273.15 °C, which is absolute zero, the lowest possible temperature.
• 100 °C is the boiling point of water at normal atmospheric pressure.

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

• The shortest distance between two points is called displacement.
• Displacement is a measure of the straight-line distance between two points.
•  It is a scalar quantity.

Key Point: The longest distance between two points is called the circumference (if the points are on a circle) or a diagonal (if the points are on a polygon or a rectangle).

Explanation

Plasmodium is a genus of protozoan parasites that cause malaria.

There are several species of Plasmodium that can infect humans, including P. falciparum, P. vivax, P. ovale, and P. malariae.

Explanation

Acetic acid (CH3COOH) is a weak acid that only partially dissociates in water, forming a weak electrolyte solution.

It does not fully dissociate into ions like strong acids (like HCl) or strong bases (like KOH).

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.