The highest tides, known as spring tides, occur during the time of the new moon and the full moon. During these phases, the Sun, Moon, and Earth are aligned in a straight line, causing their combined gravitational forces to produce higher high tides and lower low tides. This alignment amplifies the tidal effect, resulting in the strongest tidal ranges.

Other options (for context)

• Solar eclipse: Can coincide with a new moon but is not directly responsible for higher tides.
• Lunar eclipse: Occurs during a full moon but does not always produce exceptionally high tides.
• Volcanoes: Have no relation to tidal movements; tides are caused by gravitational forces, not geological activity.

Explanation: Acupuncture is an ancient form of traditional Chinese medicine that involves the insertion of very thin needles through the skin at specific points, called acupoints. It is based on the concept of balancing the flow of life energy (Qi or Chi) through pathways in the body known as meridians. When these energy flows are blocked or imbalanced, it can cause illness or pain.

By stimulating specific acupoints, acupuncture is believed to restore the normal energy flow and help the body heal itself. It is commonly used to treat:

• Chronic pain (e.g., back, neck, and joint pain)
• Migraines and headaches
• Arthritis and muscle stiffness
• Stress and anxiety

Scientific View: Modern research suggests that acupuncture may stimulate nerves, muscles, and connective tissue, boosting the body’s natural painkillers (endorphins).

Diseases like Polio and Chicken Pox are caused by viruses. The Polio virus attacks the nervous system and can lead to paralysis, while the Varicella-zoster virus causes Chicken Pox, characterized by itchy blisters and fever. Viruses are acellular infectious agents that can reproduce only inside the living cells of a host organism.

Other options (for context)

• Bacteria: Cause diseases like tuberculosis, cholera, and typhoid, not polio or chicken pox.
• Protozoa: Cause diseases such as malaria and amoebiasis.
• Algae: Generally non-pathogenic; they do not cause human diseases like polio or chicken pox.

Explanation: The onion is a modified underground stem called a bulb. It consists of a short, disc-like stem (the basal plate) surrounded by concentric fleshy leaf bases that store food. The roots emerge from the underside of the basal plate, and new shoots grow from the center. Thus, the onion bulb serves as a storage organ for nutrients and helps in vegetative propagation.

Explanation: The nephron is the basic structural and functional unit of the kidney. Each human kidney contains about 1 to 1.5 million nephrons. A nephron consists of two main parts — the renal corpuscle (Bowman's capsule and glomerulus) and the renal tubule. It performs three main functions: filtration of blood, reabsorption of essential substances, and secretion