In the early days of the solar system, many planetesimals orbited the Sun. The theory has it that one large planetesimal the size of Mars struck a glancing blow to the molten Earth. How did this event contribute to the formation of the Moon?

This event led to the breaking away of a part of earth and the part was held on by earth’s gravity and this part became the moon.

Explanation:

The formation of moon was after the formation of the earth. In the initial years of the formation of earth it was affected by several asteroid hits and comets. Small planets referred to as planetesimals  also kept continuously affecting the earth. Before 4.5 billion years ago a planetesimal which was about the size of Mars hit earth.

This hit led to the breaking away of a part of earth. The part which was sent to space by the hit was caught by the gravity of the earth and the part started orbiting around the earth. The similarity of the rocks in moon to that of earth is attributed to the fact that moon was actually formed from earth.

The moon and earth keeps influencing each other. The moon’s effect reduced the speed of earth’s rotation and the moon keeps moving away from the earth due to the influence of earth.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.