The rate of energy coming from the Sun changes slightly day to day. .It has been suggested that changes in solar output might affect our climate—both directly, by changing the rate of solar heating of the Earth and atmosphere, and indirectly, by changing cloud forming processes.
The axial tilt angle affects climate largely by determining which parts of the earth get more sunlight during different stages of the year Likewise, during winter for the northern hemisphere, there would be fewer hours of daylight because the northern hemisphere would essentially be pointed away from the sun.
If an asteroid were to strike land or a shallow body of water, it would eject an enormous amount of dust, ash, and other material into the atmosphere, blocking the radiation from the Sun. This would cause the global temperature to decrease drastically.
The Sun's irradiance has its greatest effect on Earth's upper atmosphere, while the lower atmosphere insulates Earth from the increased heat. If the Sun were driving Earth's warming, one would expect to see that upper atmosphere getting increasingly hot.\
I think the correct answer would be A. The yolk sac becomes the placenta. It is membranous sac that is attached to the embryo. It provides all the nutrition and the blood cells needed by the embryo. It is also called the umbilical vesicle.
