At Andaman, authorities do not allow tourists to collect shells from beaches. Why it must be so?

Answer the following : During a field visit an Andaman, Rahul observed that some volunteers were not allowing tourist to collect shells from the beaches. When he asked his teacher, she replied that it is an attempt to protect the ecosystem and explained the importance of seashells. What might have been her explanation?

Why do molluscs have shells?

Why do molluscs have shells?

For the school athletic meet, Shriya was advised to consume either Glucon-D or fruit juice but no sugarcane juice. Why it must be so?"

Apparatus: Bars of stainless steel, aluminium and copper, a candle, a burner, pins, etc. : Procedure: Take stainless steel (or iron), copper and aluminium bars, each about 30 cm long and having the same shape. Apply wax spots with the help of candle at a distance of 2 cm from each other on all the three bars. Stick a pin in each of these spots so that it is upright. Now insert the ends of all three bars into a flame at the same time. for a while. What do you see? From which bar do the pins start falling first? Why?

Answer the following questions : Take two similar pages from your notebook. Crumple one paper and allow this and the other paper to fall on the ground simultaneously. What do you observe ?

Bring 'active dry yeast' from the market. Mix a spoonful of yeast, two spoonful sugar with a sufficient quantity of lukewarm water in a bottle. Fix a colourless, transparent balloon on the mouth of that bottle. What changes do you observe after 10 minutes? Mix limewater with the gas accumulated in the balloon. Collect that lime water in a beaker and observe it. What do you notice?

Why do the son of colour blind's father is not suffering from the same trait?

With what minimum speed v must be small ball be pushed inside a smooth vertical tube from a height h so that it may reach the top of the tube?