Ans. Veins carry carbon dioxide-rich blood from all parts of the body back to the heart.
Ans. There are valves present in veins which allow blood to flow only towards the heart.
Ans. The heart is located in the chest cavity with its lower tip slightly tilted towards the left.
Ans. The pulmonary artery carries carbon dioxide-rich blood from the right ventricle to the lungs.
Ans. Excretory system of humans consists of two kidneys, two ureters, a urinary bladder, and urethra.
Ans. The vascular tissue for the transport of water and nutrients in the plant is called the xylem.
Ans. Veins are the blood vessels that carry blood from all parts of the body back to the heart.
Ans. Veins are the vessels which carry carbon dioxide-rich blood from all parts of the body back to the heart.
Ans. Aquatic animals like fishes, excrete cell waste as ammonia which directly dissolves in water.
Ans. Some land animals like birds, lizards, snakes excrete a semi-solid, white coloured compound (uric acid).
Ans. The partition between the chambers helps to avoid mixing up of blood rich in oxygen with the blood rich in carbon dioxide.
Ans. Sweating plays an important role in cooling the body by allowing water to evaporate off the skin, resulting in a loss of body heat.
Ans. When our cells perform their functions, certain waste products are released. These are toxic and hence need to be removed from the body.
Ans. Atrium - The two upper chambers of the heart are called the atria (singular: atrium).
Ventricle - The two lower chambers of the heart are called the ventricles.
Ans. The xylem forms a continuous network of channels that connects roots to the leaves through the stem and branches and thus transports water to the entire plant.
Ans. The walls of the chambers of the heart are made up of muscles. These muscles contract and relax rhythmically. This rhythmic contraction followed by its relaxation constitutes a heartbeat.
Ans. The kidneys perform the essential function of removing waste products from the blood and produce urine, composed of wastes and extra fluid. It helps in regulating the water fluid levels.
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