Why are temperatures cooler in the
northern hemisphere at this time?

Earth spins on an angle, so the Northern hemisphere is towards the sun in the summer, making it warmer and having the temperature increase, so the opposite of that is that in the winter, the Northern Hemisphere tilts away from the sun, making the temperatures decrease.

Hope this helps!

Explanation:

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.