Q641. Cuscuta (Amarbel) is an example of which type of plant nutrition?
RAS Prelims MCQ Practice
9,654 RAS Prelims practice MCQs with the correct answer and a clear explanation for each. Filter by subject and chapter.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
Showing 641–650 of 9654 questions
Browse by subject
Q642. Given below are two statements: one is labelled as Assertion (A) and the other is labelled as
Reason (R).
Assertion (A): The inner lining of the human stomach is protected from the action of hydrochloric acid (HCl).
Reason (R): The stomach secretes mucus that coats the inner lining, preventing acid damage.
Reason (R).
Assertion (A): The inner lining of the human stomach is protected from the action of hydrochloric acid (HCl).
Reason (R): The stomach secretes mucus that coats the inner lining, preventing acid damage.
Explanation
The stomach produces highly concentrated hydrochloric acid to assist in digestion and kill bacteria. To prevent this strong acid from digesting the stomach’s own muscular walls, specialized cells secrete a thick layer of mucus. This mucus acts as a protective barrier, neutralizing the acid near the surface and preventing ulcers or chemical damage to the sensitive inner lining of the organ.
Q643. The primary role of bile juice in digestion is to:
Explanation
Bile is a digestive fluid produced by the liver and stored in the gallbladder. Its primary function in the small intestine is the emulsification of fats. Bile salts break down large, insoluble fat globules into many smaller droplets called micelles. This significantly increases the surface area available for lipase enzymes to act upon, facilitating the efficient chemical digestion and subsequent absorption of lipids.
Q644. Finger-like projections in the small intestine that significantly increase the surface area for absorption are known as:
Explanation
Villi are numerous small, finger-like projections that line the inner surface of the small intestine. Their primary purpose is to dramatically increase the surface area available for the absorption of digested food. Each villus contains a network of blood capillaries and a specialized lymph vessel called a lacteal, which work together to transport absorbed nutrients efficiently from the digestive tract.
Q645. Which of the following vitamins is water-soluble and must be consumed regularly in the diet?
Explanation
Vitamins are classified into two groups based on their solubility. Vitamins A, D, E, and K are fat-soluble and can be stored in the body’s tissues. In contrast, Vitamin C and the B-complex vitamins are water-soluble. Because they are not stored in significant amounts and are easily excreted, they must be consumed regularly in the daily diet to maintain health.
Q646. A diet deficient in Vitamin A is most likely to cause which of the following conditions?
Explanation
Vitamin A is essential for maintaining healthy vision, particularly in low-light conditions, as it is a critical component of the pigment rhodopsin found in the retina. A chronic deficiency of Vitamin A can lead to night blindness, where an individual has difficulty seeing in the dark. If left untreated, severe deficiency can progress to permanent eye damage and even total blindness.
Q647. Kwashiorkor, a form of severe malnutrition, is primarily caused by a deficiency of:
Explanation
Kwashiorkor is a severe form of malnutrition caused by a diet that is critically deficient in proteins, even if the total caloric intake from carbohydrates is sufficient. It is most commonly seen in children in developing regions. Characteristic symptoms include a bloated abdomen, thinning hair, and swelling of the limbs, resulting from fluid imbalance and the body’s inability to maintain tissues properly.
Q648. Match the vitamins and minerals in List I with their corresponding deficiency diseases in List II.
| Vitamin | Deficiency Disease |
|---|---|
| A. Vitamin B1 (Thiamine) | i. Scurvy |
| B. Vitamin C (Ascorbic acid) | ii. Anemia |
| C. Vitamin D (Calciferol) | iii. Rickets |
| D. Iron (Mineral) | iv. Beriberi |
Explanation
Specific nutrient deficiencies lead to well-known diseases. A lack of Vitamin B1 causes Beriberi, affecting the nervous system. Vitamin C deficiency results in Scurvy, characterized by bleeding gums and poor wound healing. Vitamin D is necessary for bone health; its absence leads to Rickets. Iron is a key component of hemoglobin, and its deficiency results in anemia, causing fatigue.
Q649. Bakelite and melamine are examples of which type of polymer?
Explanation
Bakelite and melamine are classified as thermosetting plastics. Unlike thermoplastics, which can be melted and reshaped multiple times, thermosetting polymers undergo a permanent chemical change during their initial molding process. They form extensive cross-links between polymer chains, creating a rigid, heat-resistant structure that does not soften upon reheating. This makes them ideal for electrical insulators and durable, heat-resistant kitchenware surfaces.
Q650. The process of heating natural rubber with sulfur to improve its strength and elasticity is called:
Explanation
Vulcanization is a chemical process used to enhance the physical properties of natural rubber. By heating the raw rubber with sulfur, cross-links are formed between the long polymer chains. This modification significantly improves the material’s strength, durability, and elasticity while reducing its tackiness. Vulcanized rubber is resistant to temperature changes, making it suitable for manufacturing tires, hoses, and industrial products.Answer key for these questions
| Q | Correct answer |
|---|---|
| 641 | (c) Parasitic |
| 642 | (a) Both A and R are true and R is the correct explanation of A. |
| 643 | (c) Emulsify large fat globules into smaller micelles |
| 644 | (b) Villi |
| 645 | (d) Vitamin C |
| 646 | (a) Night blindness |
| 647 | (c) Proteins |
| 648 | (a) A-iv, B-i, C-iii, D-ii |
| 649 | (d) Thermosetting plastics |
| 650 | (b) Vulcanization |
Frequently asked questions
How many RAS Prelims practice MCQs are there on RAS Prelims?
This page has 9654 practice MCQs on the RAS Prelims syllabus. Each has the correct answer, and most have an explanation.
How should I practise MCQs for RAS Prelims?
Attempt each question first, then open the answer and read the explanation. Practise one chapter at a time, note the facts you got wrong and revise them. Repeat the chapter after a few days.
Are these actual RAS Prelims past-paper questions?
No. These are practice questions written for the RAS Prelims syllabus. They follow the pattern the exam uses: factual questions, statement-based questions, match-the-list and assertion-reason.