Neutrophils are the most common type of white blood cell, comprising about 50-70% of all white blood cells. They are phagocytic, meaning that they can ingest other cells, though they do not survive the act. Neutrophils are the first immune cells to arrive at a site of infection, through a process known as chemotaxis.
One of the basic theories stipulates that increasing interest rates raise consumers' and manufacturers' costs, which, in turn, reduces the amount of time and money people spend driving. Less people on the road translates to less demand for oil, which can cause oil prices to drop.
Reason No. 2: Oil price has been falling. One of the primary reasons why your gas prices rise or fall is the fluctuation in the price of crude oil. U.S. refineries buy several million barrels of oil every day to supply the world's biggest economy, so even small price changes make a big difference.