Question

sst class 7 chapter 1 medival period bookwork cbse​

Answer 1

Answer:

Lysosomes pass through various stages in the same cell. The phenomenon is called polymorphism or existence of more than one morphological form. Depending upon their morphology and function, there are four types of lysosomes— primary, secondary, residual bodies and auto-phagic vacuoles (Fig. 8.33).Douglas-fir, spruce, true fir, beech, and maple are toward the top of the list for oxygen release.why do we lose smelling sense?will we get it by treatment?Industrial revolution has been brought about by the homo sapiens in the tool making technique.

Explanation:

Let distance from A to B=x  km= distance from B to A.

Time taken by train from A to B =60x hr 

Time taken by train  from B to A =80x hr

Total time taken by train =60x+80x=2407x hr

average speed=total timetotal distance=2407x2x=7480 km h−1