Give reason:
The measuring devices used in the markets should be monitored from time to time.​

to maintain uniformity in measurement and prevent fraud during buying and selling of goods

For the purpose of deriving the value of the kilogram, the Central Government shall cause to be prepared a national prototype of the kilogram and shall cause its accuracy to be certified by the International Bureau of Weights and Measures in terms of the international prototype of the kilogram and shall deposit .

Explanation:

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.

the best answer for these questions would be:

1.            c. is smaller

2.            d) concrete operational

3.            b) interaction with the environment – the children interact with their environment can them learn more.

4.            a) parents who reason openly with children can limit a child’s cognitive ability.