Q.23 What are the difficulties historians face in using manuscripts?
Q.24 'Improvement in water and sanitation can control many diseases' explain with the help of
examples.
Q.25 How are minerals useful to humankind?
Q.26 Why were the Delhi Sultan interested in cutting down forests? Does deforestation occur
for the same reasons today?
Q. 27 What are ox-bow lakes?
Answers
23= The historians face several difficulties in using manuscripts. There was no printing press in those days so scribes copied manuscripts by hand. Manuscript copying is not an easy job. As scribes copied manuscripts, they also introduced small changes—a word here, a sentence there.
24= Water and sanitation are the basic necessities for the maintenance of our health. Poor quality of water causes a lot of health problems. Similarly, poor sanitation causes epidemics by giving birth to dangerous insects and worms. ... Improvement in water and sanitation can control these happenings.
25= Just like vitamins, minerals help your body grow, develop, and stay healthy. The body uses minerals to perform many different functions — from building strong bones to transmitting nerve impulses. Some minerals are even used to make hormones or maintain a normal heartbeat.
26= The Delhi Sultans were interested in cutting down forests because they wanted to extend cultivation. Cultivation was the only means by which they could collect more land revenue. But today forests are cut down for the establishment of industrial units and accommodation of the ever- growing population.
27= An oxbow lake is a lake located in an abandoned meandering channel, and hence on a floodplain. Although a simple lunate shape is common, reflecting the fact that single meander loops are typically isolated, there is no requirement that limits a cutoff to a single loop. ... Oxbow Lake.