Answer:
Option d) Gulf stream
Explanation:
The Gulf stream along with the drift in North Atlantic which is the northern extension of the Gulf stream is a warm current of Atlantic ocean.
It has its origin in the Gulf of Mexico and extends upto the tip of Florida along the coastlines of the eastern part of the NewfoundLand and the U.S before passing through the Atlantic Ocean.
These are responsible for the milder winter climates of Northern Europe and the U.S
The mantle is actually a liquid. The intense heat of the core of the Earth causes the mantle to move in convection currents.
The north end of Earth's axis is tilted toward the sun from March 21 until
September 21 ... Spring and Summer in the northern hemisphere, which
includes North America.
