What is benefit of high-yield crops?

The benefits of a high-yield crops are:

-The improved varieties of crops give us more yields per hectare.

-The high yielding varieties of crops are dwarf. Due to short height, their plants are stronger and hence can withstand strong winds. The problem of lodging is less in these improved varieties.

-The high yield varieties of crops give better response to fertilizers. This means that when fertilizers are supplied to high yielding varieties their yield increases substantially. This is not so in case of traditional varieties.  

-The high yielding varieties of crops take less time for maturing. As a result, some additional crop can be raised in the spare time thus saved.

the answer is b. hope this !

seismic wave -

an elastic wave in the earth produced by an earthquake or other means.

explanation: