Which chemical is sprayed to break the dormancy of buds?

The period of suspended growth due to exogenous conditions is termed as

Which of the following is not a man-made method to overcome seed dormancy?
$(I)$ Seed coat broken by using knives,sandpapers,etc.
$(II)$ Passage of seed through the digestive tract of animals.
$(III)$ Effect of inhibitory substances can be removed by subjecting the seeds to chilling conditions.
$(IV)$ By application of certain chemicals like gibberellic acid and nitrates.

Which plant part shows upward flow of nutrients in higher quantity?

Give scientific reasons: Water is essential for germination.

Give scientific reasons: The seeds which are deeply sown in soil or in water-logged soils,often fail to germinate.