International Women's Day is celebrated globally on March 8th every year. This day serves as a focal point in the movement for women's rights, highlighting issues such as gender equality, reproductive rights, and violence and abuse against women. It is an official holiday in many countries worldwide.

World Population Day is an annual event observed on July 11th, established by the Governing Council of the United Nations Development Programme in 1989. The day is intended to raise awareness about global population issues, such as the importance of family planning, gender equality, poverty, maternal health, and human rights. It serves as a platform to discuss the challenges and opportunities associated with the world's growing population and its impact on sustainable development.

The flash point is a chemical property of a liquid, defined as the lowest temperature at which it can vaporize to form an ignitable mixture in air. It is primarily used in fire safety and engineering, not in climatology. Conversely, the dew point is a measure of atmospheric humidity, the Stevenson Screen is a standard enclosure for meteorological instruments, and a hydrogram represents water flow data, all of which are relevant to climate studies.

The South Asian Association for Regional Cooperation (SAARC) includes countries that share land borders with India, such as Pakistan, Nepal, Bhutan, and Bangladesh, alongside island nations like Sri Lanka and the Maldives. This statement highlights the regional connectivity centered around India's geography, which is a common way to categorize the member states in geopolitical studies.

The Gobi Desert is a vast, cold desert located in East Asia, spanning parts of northern China and southern Mongolia. While the other options listed are also correctly matched to their respective continents, the Gobi is frequently cited in geographical studies as a primary example of a cold desert environment in Asia, distinguishing it from the hot, arid deserts found in other regions.

Sandstone is a sedimentary rock composed of mineral particles or rock fragments, which typically results in higher porosity and permeability compared to dense, crystalline igneous rocks like basalt and granite. These spaces between the grains allow for the storage and movement of fluids, making it a significant reservoir rock in geological studies.

In the context of traditional astronomical classifications, Pluto is cited as having the longest orbital period among the listed options. While Pluto is now classified as a dwarf planet, it remains a significant object in solar system studies regarding orbital mechanics.

The Sun is significantly larger than the Earth. Scientific measurements confirm that the diameter of the Sun is approximately 109 times the diameter of the Earth. This massive scale difference is a fundamental fact in solar system studies, highlighting the Sun's dominant size compared to the terrestrial planets orbiting it.

Sandstone is classified as an arenaceous sedimentary rock. It is primarily composed of sand-sized mineral particles or rock fragments, typically quartz or feldspar. These grains are cemented together over time by minerals like silica, calcium carbonate, or iron oxide, forming a durable rock structure often used in construction and geology studies.

The Jack Merison line is historically referenced in certain geographical contexts as a boundary marker between the nations of Peru and Brazil. It serves as a point of reference in regional border studies.