Attock Fort was built by the Mughal Emperor Akbar in 1581. It is located near the Indus River in present-day Pakistan and was constructed for strategic military purposes. The fort played a crucial role in defending the northwestern frontier of the Mughal Empire against invasions from Central Asia. Akbar was known for strengthening the empire through administrative reforms and military infrastructure. Attock Fort was part of his broader strategy to secure trade routes and maintain control over key regions. Babur founded the Mughal Empire but did not build this fort. Sher Shah Suri was known for road construction, including the Grand Trunk Road, while Aurangzeb ruled later and did not construct Attock Fort. Thus, Akbar is the correct answer. The fort remains an important historical and architectural landmark in Pakistan today.

Amjad Hussain Sial from Pakistan served as the Secretary-General of SAARC (South Asian Association for Regional Cooperation). SAARC is a regional organization that promotes economic and cultural cooperation among South Asian countries. The Secretary-General is responsible for coordinating activities, implementing decisions, and facilitating cooperation among member states. The position rotates among member countries. Antonio Guterres is the UN Secretary-General, not SAARC. Ajay Bisaria is an Indian diplomat, and Arjun Bahadur Thapa is a former SAARC Secretary-General. Thus, Amjad Hussain Sial is the correct answer in this context, reflecting leadership within regional cooperation frameworks.

Zahid Hussain was the first Governor of the State Bank of Pakistan when it was established in 1948. The State Bank serves as the central bank of the country and is responsible for monetary policy, currency issuance, and financial stability. As the first governor, Zahid Hussain played a crucial role in setting up the banking system of the newly independent Pakistan. His leadership helped establish financial institutions and regulatory frameworks. Other options include later officials or unrelated figures. Shamshad Akhtar served much later, while Malik Ghulam Muhammad was a political figure. Thus, Zahid Hussain is the correct answer, marking an important milestone in Pakistan’s economic history.

Wasim Sajjad holds the record for being the longest-serving Chairman of the Senate of Pakistan. He served multiple terms and played a significant role in parliamentary proceedings. The Chairman of the Senate is the presiding officer of the upper house and is second in line for the presidency. Wasim Sajjad’s long tenure reflects political stability and experience in legislative affairs. Other options either served shorter terms or held different positions. Thus, Wasim Sajjad is the correct answer, highlighting an important figure in Pakistan’s parliamentary history.

Kurt Waldheim served as the fourth Secretary-General of the United Nations from 1972 to 1981. The Secretary-General is the chief administrative officer of the UN and plays a key role in international diplomacy. Waldheim’s tenure focused on global peace efforts and conflict resolution during the Cold War period. His role involved mediating disputes and representing the UN on international platforms. Thus, he is ranked as the 4th Secretary-General, making option D correct.

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are primarily composed of proteins, which are made up of amino acids folded into specific three-dimensional structures. This structure is crucial because it determines the enzyme’s active site, where substrates bind and reactions occur. Enzymes are highly specific, meaning each enzyme typically catalyzes a particular reaction. Vitamins and minerals may act as cofactors or coenzymes, assisting enzyme function, but they are not the main structural components. Carbohydrates do not form enzymes. Thus, proteins are the correct answer. This concept is fundamental in biochemistry and helps explain how metabolic processes occur efficiently in living organisms.

Edward Jenner, an English physician, is credited with developing the first successful vaccine in 1796. He discovered that milkmaids who had contracted cowpox were immune to smallpox, a deadly disease at the time. Jenner tested his theory by inoculating a young boy with material from cowpox lesions and later exposing him to smallpox. The boy did not develop the disease, proving immunity. This discovery laid the foundation for immunology and modern vaccination. It led to the eventual eradication of smallpox worldwide. Other options are incorrect as they do not match the historical timeline. Thus, 1796 is the correct answer, marking a major breakthrough in medical science and public health.

In flowering plants, after fertilization occurs, the ovary of the flower develops into the fruit. The ovary contains ovules, which, after fertilization, develop into seeds. The fruit serves to protect the seeds and aid in their dispersal. Different types of fruits develop depending on the plant species and structure of the ovary. The stigma is the receptive part of the pistil for pollen, anthers produce pollen, and petals attract pollinators. None of these develop into fruit. Thus, the ovary is the correct answer. This concept is important in plant reproduction and agriculture. Understanding fruit development helps explain how plants reproduce and spread in different environments.

Parthenocarpy is the development of fruit without fertilization, resulting in seedless fruits. This phenomenon can occur naturally or be induced artificially using plant hormones. Common examples include bananas and seedless grapes. These fruits are commercially valuable because they are easier to eat and often preferred by consumers. In normal fruit development, fertilization triggers seed formation. In parthenocarpy, this step is bypassed, but fruit growth still occurs. Other options are incorrect because parthenocarpy specifically refers to seedless fruit production. Thus, seedless fruit is the correct answer. This concept is important in botany and agriculture, especially in improving crop quality and market value.

Vitamin D is essential for calcium absorption and bone health. Its deficiency leads to rickets in children, a condition characterized by soft and weak bones, leading to deformities such as bowed legs. In adults, vitamin D deficiency can cause osteomalacia, which results in bone pain and muscle weakness. Vitamin D is obtained from sunlight exposure and certain foods. Scurvy is caused by vitamin C deficiency, and night blindness is due to vitamin A deficiency. Fibrosis is unrelated. Thus, rickets is the correct answer. This highlights the importance of balanced nutrition and sunlight exposure for maintaining healthy bones.