Correct Answer: a) Both 1 and 2

Explanation:

1. Statement 1: Western Europe receives rainfall in all months.

– Western Europe experiences a maritime climate, heavily influenced by the North Atlantic Drift (a warm ocean current) and the prevailing westerly winds. This region typically receives rainfall throughout the year due to the consistent influence of moist air masses from the Atlantic Ocean. The rainfall is evenly distributed across all months, with no distinct dry season. Hence, this statement is correct.

2. Statement 2: Western Europe is located in the belt of Westerlies.

– The westerlies are prevailing winds that blow from the west to the east in the mid-latitudes (approximately 30° to 60° latitude in both hemispheres). Western Europe lies within this belt of westerlies, which brings moist air from the Atlantic Ocean, contributing to its moderate temperatures and year-round precipitation. Therefore, this statement is also correct.

Since both statements are correct, the correct answer is a) Both 1 and 2.

Correct Answer: a) 2, 4, 3, 1

Explanation:

1. Pontic Mountains: These are located in northern Turkey, near the Black Sea. They lie to the east of the Zagros Mountains.

2. Zagros Mountains: These are located in Iran and are the westernmost among the given mountains. They extend from the Persian Gulf to the northwestern part of Iran.

3. Hindu Kush Mountains: These are located in Afghanistan and extend into Pakistan. They are situated to the east of the Pontic Mountains.

4. Karakoram Mountains: These are located in northern Pakistan, India, and China. They are the easternmost among the given mountains.

Correct answer: a) 2, 4, 3, 1

Correct Answer: a) Pulmonary vein

Explanation:

In the human circulatory system, veins typically carry deoxygenated blood back to the heart, while arteries carry oxygenated blood away from the heart. However, the pulmonary vein is an exception to this rule.

The pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart after the blood has been oxygenated in the lungs during gas exchange. This is a unique feature of the pulmonary vein, distinguishing it from other veins in the body.

– Cystic vein: Drains blood from the gallbladder and carries deoxygenated blood.

– Cardiac vein: Drains deoxygenated blood from the heart muscle into the coronary sinus.

– Hepatic portal vein: Carries nutrient-rich but deoxygenated blood from the gastrointestinal tract to the liver.

Thus, the pulmonary vein is the only vein that carries oxygenated blood.

Correct Answer: d) Pancreas

Explanation:

Diabetes is a metabolic disorder primarily associated with the pancreas, an organ responsible for producing insulin. Insulin is a hormone that regulates blood sugar levels. In diabetes:

– Type 1 Diabetes: The immune system attacks the insulin-producing beta cells in the pancreas, leading to little or no insulin production.

– Type 2 Diabetes: The pancreas may produce insulin, but the body becomes resistant to it, or the pancreas cannot produce enough insulin to meet the body’s needs.

While diabetes can lead to complications affecting other organs like the kidneys (diabetic nephropathy), the root cause of the disorder lies in the dysfunction of the pancreas. Hence, the correct answer is d) Pancreas.

Correct Answer: c) SARS-CoV-2

Explanation:

The COVID-19 pandemic, which caused a global pause in various activities, was due to the novel coronavirus named SARS-CoV-2. This virus was first identified in Wuhan, China, in late 2019 and is responsible for the disease known as COVID-19. SARS-CoV-2 is part of the coronavirus family, which includes other viruses like SARS-CoV-1 (responsible for the 2002-2003 SARS outbreak) and MERS-CoV (responsible for the Middle East Respiratory Syndrome).

– SARS-CoV-1: Caused the SARS outbreak in 2002-2003 but was not responsible for the COVID-19 pandemic.

– H5N1: Refers to a strain of avian influenza (bird flu) and is unrelated to the COVID-19 pandemic.

– MERS-CoV: Caused the Middle East Respiratory Syndrome outbreak in 2012 but is not linked to the recent pandemic.

Thus, the correct answer is SARS-CoV-2, which led to the global health crisis starting in 2019.

Correct Answer: b) 2v1v2 / (v1 + v2)

Explanation:

The average speed is defined as the total distance traveled divided by the total time taken.

1. Let the total distance be “D”.

– The first half of the distance is D/2, and the second half is also D/2.

2. Time taken to cover the first half of the distance:

Speed = Distance / Time, so Time = Distance / Speed.

For the first half, the time taken is:

t1 = D/2 / v1 = D / 2v1

3. Time taken to cover the second half of the distance:

Similarly, for the second half, the time taken is:

t2 = D/2 / v2 = D / 2v2

4. Total time for the journey:

The total time is the sum of t1 and t2:

t_total = t1 + t2 = D / 2v1 + D / 2v2

Taking a common denominator:

t_total = D(v2 + v1) / 2v1v2

5. Average speed formula:

The average speed is given by:

Average speed = Total distance / Total time

Substituting the values:

Average speed = D / t_total = D / (D(v1 + v2) / 2v1v2)

Simplify the expression:

Average speed = 2v1v2 / (v1 + v2)

Final Answer: The average speed during the whole journey is: b) 2v1v2 / (v1 + v2)

Correct Answer: a) Dam’s length – 825.8 metres

Explanation:

The Ramganga Dam, also known as the Kalagarh Dam, is an embankment dam on the Ramganga River 3 km (2 mi) upstream of Kalagarh in Pauri Garhwal district, Uttarakhand, India. It is located within the Jim Corbett National Park.

The dam is part of the Ramganga Multipurpose Project — an irrigation and hydroelectric project. It supports a 198 MW power station and provides water for the irrigation of 57,500 ha (142,086 acres) of farmland. In addition, it provides for flood control and recreation. Construction on the dam began in 1961 and it was completed in 1974. The three generators in the power station were commissioned in December 1975, November 1976 and March 1977.

The dam is a 128 m (420 ft) tall and 630 m (2,067 ft) long earth and rock-fill embankment dam with 10,000,000 m³ (13,079,506 cu yd) of fill. 

Correct Answer: b) Pathogens

Explanation:

A disease-causing microorganism is referred to as a pathogen. Pathogens are agents, such as bacteria, viruses, fungi, or protozoa, that can cause diseases in humans, animals, or plants. While some bacteria and protozoa can be pathogens, not all of them are harmful. For example, many bacteria are beneficial and play essential roles in processes like digestion and nutrient cycling.

On the other hand:

– Archaea are microorganisms that are generally not known to cause diseases in humans. They are often found in extreme environments and are not pathogenic.

– Bacteria can be either beneficial or harmful. Only certain types of bacteria are pathogens.

– Protozoa are single-celled organisms, and while some can cause diseases (e.g., malaria caused by Plasmodium), not all protozoa are harmful.

Correct Answer: d) Emulsion

Explanation:

Milk is an example of an emulsion, which is a type of colloid where tiny droplets of one liquid are dispersed in another liquid that is immiscible (does not mix). In the case of milk, it is an emulsion of fat droplets dispersed in water. The fat and water do not naturally mix, but milk contains emulsifying agents (like proteins) that stabilize the mixture.

Here’s why the other options are incorrect:

– a) Foam: A foam is a colloid where gas is dispersed in a liquid or solid (e.g., whipped cream or foam on beer). Milk is not a foam.

– b) Sol: A sol is a colloid where solid particles are dispersed in a liquid (e.g., paint or muddy water). Milk does not fit this description.

– c) Aerosol: An aerosol is a colloid where solid or liquid particles are dispersed in a gas (e.g., fog or smoke). Milk is not an aerosol.

Correct Answer: d) NaHCO3

Explanation:

Baking soda is chemically known as sodium bicarbonate, and its chemical formula is NaHCO3. It is a white crystalline compound that is commonly used in baking as a leavening agent. When it reacts with acids (like vinegar or lemon juice), it releases carbon dioxide gas, which helps dough rise.

– a) KHCO3: This is potassium bicarbonate, not baking soda.

– b) Na2CO3: This is sodium carbonate, also known as washing soda, which is different from baking soda.

– c) K2CO3: This is potassium carbonate, not related to baking soda.

– d) NaHCO3: This is the correct formula for baking soda.

Thus, the correct answer is d) NaHCO3.