PPSC Past Papers & Solved MCQs

Mushrooms are heterotrophic organisms that obtain nutrients by absorption, a key characteristic of the Fungi kingdom.

• Fungi (A) is correct because mushrooms are indeed fungi, characterized by their cell walls made of chitin and their method of nutrient absorption.
• Plantae (B) is incorrect; plants are autotrophic, producing their own food through photosynthesis, which mushrooms do not do.
• Animalia (C) is incorrect; animals are heterotrophic but ingest their food, and their cells lack cell walls.
• Protista (D) is incorrect; protists are a diverse group of eukaryotic microorganisms, but mushrooms have a more complex, multicellular structure and distinct fungal characteristics.

The law of universal gravitation was formulated by Isaac Newton. This foundational law describes the gravitational attraction between any two objects with mass.

• Isaac Newton (C) is correct. He published his law of universal gravitation in 1687 in his work Philosophiæ Naturalis Principia Mathematica.
• Albert Einstein (A) is incorrect; he developed the theory of relativity, which refined our understanding of gravity but did not formulate the initial law.
• Galileo Galilei (B) is incorrect; he made significant contributions to observational astronomy and the study of motion but did not formulate the law of gravity.
• Nikola Tesla (D) is incorrect; he was an inventor and electrical engineer known for his contributions to AC electricity.

Marsupials are a distinctive group of mammals known for their unique reproductive strategy. They give birth to relatively undeveloped young, which then complete their development in a specialized external structure.

• Pouch (C) is correct. Marsupials, such as kangaroos and koalas, are characterized by the presence of a marsupium, or pouch, where the young (joeys) continue to develop and nurse after birth.
• Nest (A) is incorrect; nests are typically built by birds or some rodents for shelter and raising young, not a defining feature for marsupial development.
• Burrow (B) is incorrect; burrows are underground tunnels used for shelter by many animals, but not specifically for marsupial young development.
• Den (D) is incorrect; a den is a natural or artificial shelter for wild animals, often used by carnivores, but not the specific structure for marsupial young.

Tree growth rates vary significantly depending on species, climate, and soil conditions. However, some species are renowned for their rapid growth.

• Eucalyptus (B) is correct. Many species of Eucalyptus, particularly those grown in suitable climates, are known for their exceptionally fast growth rates, often reaching impressive heights in a short period. They are widely cultivated for timber, pulp, and essential oils due to this characteristic.
• Teak (A) is incorrect; while valuable, teak is a moderately fast-growing tree, but not as fast as Eucalyptus.
• Sal (C) is incorrect; Sal is a slow to moderately growing tree, prized for its durable timber.
• Banyan (D) is incorrect; Banyan trees are known for their massive size and extensive root systems, but they are generally slow-growing.

Goitre is a condition characterized by the abnormal enlargement of the thyroid gland, located in the neck. This enlargement is often a direct result of the thyroid gland's inability to produce sufficient thyroid hormones.

• Iodine (B) is correct. Iodine is an essential trace element crucial for the synthesis of thyroid hormones. A deficiency in iodine leads to reduced hormone production, prompting the thyroid gland to enlarge in an attempt to capture more iodine, resulting in goitre.
• Vitamin D (A) is incorrect; Vitamin D is vital for bone health and calcium absorption, but its deficiency does not directly cause goitre.
• Iron (C) is incorrect; Iron deficiency causes anemia, not goitre.
• Calcium (D) is incorrect; Calcium is essential for bones and teeth, and its deficiency can lead to conditions like osteoporosis, but not goitre.

The correct answer is Inertia. Inertia is a fundamental property of matter, described by Newton's First Law of Motion, which states that an object will resist changes to its state of motion. This means an object at rest tends to stay at rest, and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

• Friction is a force that opposes motion between surfaces in contact, not the inherent resistance to change in motion.
• Gravity is a fundamental force of attraction between any two objects with mass, not the resistance to changes in motion.
• Momentum is the product of an object's mass and velocity, representing the quantity of motion, not the resistance to changes in it.

The correct answer is Hollow back. Lordosis is a medical term referring to the excessive inward curvature of the spine, particularly in the lumbar (lower back) or cervical (neck) regions. This condition is often colloquially known as "swayback" or "hollow back."

• "Curved neck" is too general; while the cervical spine has a natural lordotic curve, the term lordosis specifically refers to an exaggerated curve.
• "Swollen joints" describes inflammation or fluid accumulation in joints, a symptom of conditions like arthritis, unrelated to spinal curvature.
• "Bent knee" describes a position of the knee joint, not a spinal condition.

The correct answer is Rickets. Rickets is a condition that affects bone development in children, leading to soft and weak bones. It is primarily caused by a prolonged deficiency of Vitamin D, which is essential for the body to absorb calcium and phosphate from the diet.

• Scurvy is caused by a deficiency of Vitamin C.
• Bleeding diathesis is a general term for a tendency to bleed easily, not specifically linked to Vitamin D deficiency.
• Osteoporosis is a condition characterized by brittle and fragile bones, more commonly seen in adults, though long-term Vitamin D deficiency can contribute to it. Rickets is the specific term for children.