Questions

No. Boiling water is not a chemical change. Because in this process it doesn't loss its properties. It just changes its state i.e, from liquid state to gaseous.

Hence, Boiling water is a Physiacl change and not a chemical change.

According to 2018 January reports, Mukesh Ambani is the first richest person in India being 18th in the world, followed by Azim Premji and S.P. Hinduja in second and third places.

The process that occurs inside the chloroplasts is photosynthesis. The light from the sun is obserbed and combining with water and CO2, plants prepare food for the plants.

True, Animals in the Taiga and Alpine Biomes hibernate during winter.

The animals in taiga and alpine biomes have several different kind of adaptations for survival. Some animals that hibernate during the winter take the help of camouflage to protect itself from enemies. During this period of hibernation, they slow their rate of metabolism and also use less amount of energy to survive the harsh weather.

Ans.  Suppose the speed of boat in still water is x km/h and speed of stream is y km/h

Speedof boat in downstream = (x + y) km/h x+ y = 32 …(i) 

Speed of boat in upstream = (x – y) km/h

x – y = 28 …(ii)

Add. Eqs. (i) and (ii), we get 2x = 60

x = 30 km/h

Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms activities.