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:
Any insect unlucky enough to land on the mouth-like leaves of an Australian pitcher plant will meet a grisly end. The plant's prey is drawn into a vessel-like ‘pitcher’ organ where a specialized cocktail of enzymes digests the victim.
Now, by studying the pitcher plant's genome—and comparing its insect-eating fluids to those of other carnivorous plants—researchers have found that meat-eating plants the world over have hit on the same deadly molecular recipe, even though they are separated by millions of years of evolution.
