Solution:The above statement is true.
The sun emits heat and light. Some part of this heat and light which is emitted by the sun is absorbed by the atmosphere and some part of it is reflected back. This helps to maintain an optimum value of the temperature in the day. If this atmosphere is not present, then no absorption and reflection of the heat and light emitted by the sun would be there. Hence, without the atmosphere the earth would have been very hot during the day and very cold at night.