Answer:
Oil
Explanation:
Since, unlike oil, source like wind, solar, water etc. come naturally we don't and can't replace them but when the viscosity in oil has been used up it must be change to allow the proper functioning of the machine.
Answer: 1: allergic disorders
2. Immunodeficiency disorders
3. Autoimmune disorders
4. Cancers
In DNA, the nucleotides of one strand join to bases on the complementary strand by weak hydrogen bonds.
Out of the choices given, the water rises and falls with precipitation. The water table is the level below where the ground gets saturated with water. The correct answer is B.