While working with the car engine in a closed garage Johan suddenly felt dizzy and fainted. What is the possible reason?

Smita was working in a garage with the doors closed and automobiles engine running. After some time she felt breathless and fainted. What could be the reason? How can she be treated?

Question based on paragraph : A boy pushed his toy car on a table . The car moved ahead and stopped after travelling a certain distance . But when he kept on pushing his car , the car started moving with a uniform velocity . The boy later decided to do some adventurous activity while playing with his car , so he launched his toy car from a platform to a bucket filled with water as soon as the car landed inside the bucket , the water from the bucket splashed out and the boy enjoyed his new game .: What is the reason for splashing of water out from the bucket ?

A truck of mass 5 tons is travelling on a horizontal road with 36 km hr^-1 stops on travelling 1 km after its engine fails suddenly. What fraction of its weight is the frictional force exerted by the car of mass 1 ton i.e., car moving with same speed stops in similar distance, how much will the fraction be?

While examining the mitotic stage in a tissue, one finds, some cells with 16 chromosomes and some, with 32 chromosomes. What possible reasons could you assign to this difference in chromosome number. Do you think cells with 16 chromosomes could have arisen from cells with 32 chromosomes or vice versa?