C is the first & the second question is A
Answer: B. meteorites, UV rays
The earth's atmosphere plays an important role in shielding the space rocks and meteorites enters inside the earth due to collision with the celestial body. Due to high heat and pressure in the mesospheric layer of the atmosphere these meteorites burned up before reaching the biosphere or hydrosphere system of the earth. The UV rays are protected from entering into the earth atmosphere by the ozone layer present in the stratosphere of the atmosphere. Both meteorites and UV rays can negatively effect the human population. Therefore, the atmosphere is an agent which provides protection against them.
For the first question it is the fourth option. Cryosphere is a term for the portions of earth that are covered in water when the water is in solid form. this includes both snow and ice.
For the second question the answer is a delta is formed at the mouth of the river a sediment is carried down stream. The hydrosphere refers to all water on earth.
