Canada-United States Border. Stretching a massive 8,893 km, Canada and the United States share the longest border in the world.

1. Simlipal Bio-Reserve (Sanctuary) is located in Orissa.

2. The biosphere reserve has the largest area of sal in the whole of India. Furthermore, the tropical monsoon climate provides ideal conditions for the development of a distinctive biodiversity, highlighted by 1,076 species of vascular plants.

3. These include 93 species of orchids, 300 species of medicinal plants and 52 species of endangered flora. The two endemic species of orchid are Eria meghasaniensis and Taenia hookeriana.

4. Notable botanical species in the sanctuary include Callicarpa arborea (a species of beautyberry), Bombax ceiba (cotton tree) and Madhuca longifolia (manhua).

Answer: C) Convex Explanation: Convex mirror is used as rear view mirror in vehicles. Because the image is smaller, more image can fit onto the mirror, so a convex mirror provides for a larger field of view than a plane mirror. This is why they are useful.