While selecting a breed of crop,which characteristics of the crop are to be taken into account by the farmers?

Find out the wrong statement from the following:

State one importance of photoperiod in agriculture.

Why should biological control methods be preferred for protecting crops?

The major groups of activities for improving crop yields can be classified as:

On a voyage in their yacht,John and his father came across an iceberg. John advised his father to keep away from the iceberg. His father said that it is just a small piece of ice jutting out of the sea and there is nothing to bother. John told his father that icebergs are dangerous and narrated the story of the ship $Titanic$,which was sunk by an iceberg. John explained to his father why the iceberg was dangerous. This convinced his father,and they steered clear of the iceberg.
$(a)$ Why are icebergs in the sea dangerous?
$(b)$ What values are possessed by John and his father?