A、The number of sun flares. B、The heat of the sun. C、The sunspot cycle. D、The weather. A

Astronomers are still learning about sunspots and about their effects on us, but believe that the spots on the sun, which were first observed through a telescope by Galileo in 1610, are electrical in nature.
    Sunspots vary in size from what appear to be small specks on the sun’s surface, to at least 90,000 miles long, and 200,000 miles in length, and are visible on most clear days.
    When sunspots release their electrical energy, they shoot beams of negatively charged electrons into space, some of which escape into the Earth’s atmosphere. These electrons create electrical effects, such as the aurora borealis, or Northern Lights, cause the disruption of radio transmissions, and increase the amount of ozone in the upper atmosphere. The additional ozone may absorb more than the usual amount of the sun’s heat, which in turn may affect our weather.
    The sunspot cycle, is a recurring 11-year period over which the number of sunspots fluctuates and corresponds to the number of sun flares. An increase in the number of sun flares leads to an increase in the number of sunspots, and a decrease in the number of sun flares leads to a decrease in the number of sunspots,
    Records of sunspots have only been kept for the last 100 years or so, leaving astronomers with little to back their research and much yet to discover about this phenomenon.