Jean Piaget was a cognitive psychologist who identified four stages of development: the sensorimotor stage from birth to 2 years, the preoperational stage from age 2 to age 7, the concrete operational stage from age 7 to 11, and the formal operational stage from age 11 to adult. He identified milestones that occur at each stage.   According to Piaget, the main task of the sensorimotor stage is for the child to learn the concept of object permanence, use senses and motor skills to understand the world.

I am History.   Yes, history refers to all the past, but we can create history in the presentand it cannot be polluted in the future.

Answer: C) 2:1 Explanation: Given rate of wheat at cheap = Rs. 2.90/kg Rate of wheat at cost = Rs. 3.20/kg Mixture rate = Rs. 3/kg Ratio of mixture =            2.90                              3.20                               3 (3.20 - 3 = 0.20)            (3 - 2.90 = 0.10)   0.20 : 0.10 = 2:1   Hence, wheat at Rs. 3.20/kg be mixed with wheat at Rs. 2.90/kg in the ratio of 2:1, so that the mixture be worth Rs. 3/kg.

Answer: A) Microsoft Explanation: Microsoft has acquired Flipgrid, an education start-up with an app that lets students record and share videos on specific topics with their classmates.   Microsoft is making Flipgrid free of charge.

Answer: B) June 21 Explanation: The World Music Day is celebrated across the world on 21 June.   The day is also known as 'Fete de la Musique' after a music festival that began in France in 1982.   This Day was first celebrated on 21st June 1982.

Answer: D) Cuba Explanation: Havana is the capital city of Cuba. It's currency is Cuban Peso.

Answer: C) Phoebus Levene Explanation: Deoxyribonucleic acid (DNA) is a nucleic acid polymer composed of monomers called nucleotides. Nucleotides are composed of three components: (1) a pentose sugar; (2) a nitrogenous base; and (3) one to three phosphate groups. Phoebus Levene, a Russian biochemist was the first to discover the nucleotide and the first to correctly identify the way nucleic acid molecules, DNA.

Answer: C) 289 Explanation: Here the given number series is 270, 261, 279, 252, 289, 243 270 - 9 = 261 261 + 18 = 279 279 - 27 = 252 252 + 36 = 288 (not equals to 289) 288 - 45 = 243   Hence, the odd number in the given number series is 289.