The Northern Hemisphere receives more solar energy during one half the year than it does during the other half of the year. Which
of the following happens during the year toexplain this?
1.
2.
3.
4.
The angle that Earth is tilted on itsaxis changes.
The amount of energy that is produced bythe sun anges
The distance of the Northern Hemispherefrom the sun changes
The angle at which sunlight reaches the Northern Hemisphere changes

1) The angle that Earth is tilted on its axis changes.

Explanation:

Surface of earth received more sunlight due to the tilting of the earth toward sun. Tilting is the property of the earth in which earth rotate its one end toward the sun. This tilting of earth is responsible for the formation of seasons on the earth. Earth tilt about 23.5 degrees toward sun. If there is no tilting occurs, no seasons will be formed.

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.