Questions

On December 21, the earth is in an equivalent position on the opposite points in its orbit, So the South pole is tipped towards the sun and North pole away from it resulting in 24 hours of darkness at the North pole, as the sun is overhead on the Tropic of Capricorn. This phenomenon is winter solstice; while on June 21, North pole is tipped towards the Sun but the South pole is tipped away from the sun resulting in 24 hours of darkness on the South Pole, as the sun is overhead on the Tropic of Cancer.This phenomenon is summer solstice; while Aphelion is the position of the earth in its orbit when it is at its distant point from the sun.

Micronutrients are ne tothe nutrients which our body requires for functioning and to maintain immune to micro organisms. They include 

1) Vitamins 

2) Minerals

• Vitamins: A,B1,B2,B3,B5,B6,B8,B9,B12,C,D,E,K.

• Major minerals: calcium, magnesium, chlorine, phosphorus, potassium and sodium.

• Oligo-elements (trace minerals): iron, copper, zinc, iodine, manganese, chromium, cobalt, selenium.

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.