It is genetic - in my family there is no history of it as it is a recessive gene but my mum and dad were both carriers. In Scotland up to 13% of the population has red hair, but around 40% of the population is thought to carry the recessive gene responsible for the world's rarest natural hair colour.
On the other hand, synthetic base oil molecules are chemically controlled, which provides increased ï¬ lm strength and lubricity over petroleum oils. The performance qualities of base oils have a marked impact on the performance qualities of the ï¬ nished product.
One of the common misconceptions about these two types of engine oils is that oneâsyntheticâmust last longer than the other. In fact, both synthetic oil and regular engine oil last the same interval, but there are several other important differences between synthetic oil and conventional oil.