The Rio Earth Summit was held in June 1992 in Brazil and focused on sustainable development and environmental protection.

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.

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.

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.

Karakoram Highway length is about 1600 km connecting Pakistan and China.