Question

Question 49:
(a) What is meant by ‘heart beat’ ? What is the usual heart beat rate at rest ?
(b) What change occurs in heart beats if a person runs for a while ? Why ?

Lakhmir Singh Biology Class 10

Answer 1

a) heart beat is the pumping of our heart .the usual heart beat rate at rest is close to 60 to 100 beats per minute.

Answer 2

Answer:

Lightning

Lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground. ... Lightning causes thunder! Energy from a lightning channel heats the air briefly to around 50,000 degrees Fahrenheit, much hotter than the surface of the sun.

Precautions

✯

Avoid water during a thunderstorm. Lightning can travel through plumbing. Avoid electronic equipment of all types. Lightning can travel through electrical systems and radio and television reception systems.

✯Stay away from wire fences, clotheslines, metal pipes, rails and other metallic paths which could carry lightning to you from some distance away. Avoid standing in small isolated sheds or other small structures in open areas. In a forest, seek shelter in a low area under a thick growth of small trees.