Explanation: A solar eclipse occurs when the Moon comes between the Sun and the Earth and casts its shadow on the Earth. This happens during the new moon phase, when all three celestial bodies are almost in a straight line. Depending on the alignment, the eclipse can be total (Sun completely covered), partial (Sun partially covered), or annular (ring-shaped Sun visible). During this event, sunlight is blocked for a short time in specific areas of the Earth’s surface.

Explanation: Malaria is not caused by a virus; it is caused by a protozoan parasite of the genus Plasmodium. The disease spreads through the bite of an infected female Anopheles mosquito. The parasite enters the human bloodstream, infects liver cells, and then red blood cells, leading to recurring fever, chills, and anemia. In contrast, Smallpox, AIDS, and Flu are all viral diseases caused by the Variola virus, HIV, and Influenza virus respectively.

Explanation: The sex of a newborn baby is determined by the chromosome inherited from the father. Humans have 23 pairs of chromosomes — 22 pairs of autosomes and one pair of sex chromosomes. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The mother always contributes an X chromosome, but the father can contribute either an X or a Y. If the sperm carrying an X chromosome fertilizes the ovum, the child will be a girl (XX); if the sperm carries a Y chromosome, the child will be a boy (XY).

Sir Isaac Newton invented the Reflecting Telescope in 1668. Unlike earlier refracting telescopes that used lenses, Newton’s design used a concave mirror to reflect and focus light. This eliminated chromatic aberration (color distortion) caused by lenses and significantly improved image clarity. Newton’s reflecting telescope became a major advancement in astronomical observation.

Other options (for context)

• Thermometer: Invented by Galileo Galilei (early version) and later improved by Daniel Gabriel Fahrenheit.
• Hydraulic Accumulator: Invented by William Armstrong.
• Transistor: Invented much later (in 1947) by John Bardeen, William Shockley, and Walter Brattain.

Explanation: Penicillin was discovered accidentally by Alexander Fleming in 1928 when he observed that a fungal mold, Penicillium notatum, inhibited the growth of Staphylococcus bacteria in his culture plates. Penicillin became the first antibiotic used to treat bacterial infections and saved millions of lives during World War II. Later, scientists like Howard Florey and Ernst Boris Chain developed methods for its large-scale production.

Explanation: ROM (Read Only Memory) retains its data even when the power is turned off, making it non-volatile memory. It stores essential programs such as the computer’s firmware or BIOS, which are required for booting the system. In contrast, RAM loses all information when power is shut down.

Swine Flu is caused by the H₁N₁ virus, a subtype of the Influenza A virus. It primarily affects the respiratory system and is transmitted from person to person through droplets from coughs or sneezes. Symptoms include fever, cough, sore throat, body aches, and fatigue. The H₁N₁ pandemic in 2009 was declared a global health emergency by the World Health Organization (WHO).

Other options (for context)

• Dengue: Caused by the Dengue virus, transmitted by Aedes mosquitoes.
• AIDS: Caused by the HIV (Human Immunodeficiency Virus), not H₁N₁.
• Bird flu: Caused by the H5N1 virus, not H₁N₁.

Explanation: Electrons are negatively charged particles that revolve around the nucleus in fixed paths called orbits or shells. The nucleus contains positively charged protons and neutral neutrons, and most of the atom’s mass is concentrated in the nucleus.