How can you identify a healthy animal?

Sahil's grandfather had a prostate problem. The doctor advised him to go in for an ultrasound. Sahil accompanied his grandfather to a diagnostic centre. His grandfather went through the process and was given a photograph.
$(a)$ What is the principle of ultrasound? What waves are used for this purpose?
$(b)$ Name four other areas in which the ultrasound is used as a diagnostic tool.
$(c)$ What value did Sahil imbibe about ultrasound?

The kind of flowers available determines the taste of honey.

What is a $GM$ crop? Name any one such crop which is grown in India.

On what factors do the growth of plants and flowering depend?

$(a)$ $A$ farmer wants to harvest more than two varieties at a time from his crop field. He has no idea about the cropping patterns. Suggest one method to get the desired result. Also,state three advantages of this cropping pattern.
$(b)$ Name any two fodder crops.