Consider the following statements and select the correct answer using the code given below: 1. The age of the atmosphere is about 600 million years. 2. The composition of the atmospheric gases is constant. 3. The gases of the homosphere are evenly mixed 4. The heterosphere lies 80 km above the sea level.

Consider the following statements and select the correct answer using

1.	Consider the following statements and select the correct answer using the code given below: 1. The age of the atmosphere is about 600 million years. 2. The composition of the atmospheric gases is constant. 3. The gases of the homosphere are evenly mixed 4. The heterosphere lies 80 km above the sea level.
A.	1, 2 and 3 are correct
B.	1, 2 and 4 are correct
C.	1, 3 are 4 are correct
D.	1, 2, 3 and 4 are correct
Answer» D. 1, 2, 3 and 4 are correct