Static crashes are heard on radio when a lightning flash occurs-even if the lightning occurs far away .Why does this happen?

Where and when does replication occur?

When does a drought occur?

When orange solution containing Cr_2O_7^(2-) ion is treated with an alkali, a yellow solution is formed and when H^+ ions are added to yellow solution, an orange solution is obtained. Explain why does this happen ?

In these question, a statement of assertion followed by a statement of reason is given .Choose the correct answer out of the following choices: Assertion and reason both are correct statements and reason is correct explanation for assertion. Assertion and reason both are correct statements but reason is not correct explanation for assertion. Assertion is correct statement but reason is wrong statement. Assertion is wrong statement but reason is correct statement. Assertion: The flash of lightning is seen before the sound of thunder is heard. Reason: Speed of sound is greater than speed of light.