Hey kiddo.
It takes about 365 days, for Earth to orbit the Sun. At 67,000 miles an hour it does so. An elementary way of knowing this concept is knowing how many days are in a year. There are 365 days in a year, thus it takes 365 days for earth to travel around the sun. It may be 366 if you are including the leap year that comes to past in intervals of 4 years. The next leap year is in 2020.
Option D is the correct answer. Demographics of a population are different aspects of their characteristics, such as age.
Investigate past climate and atmospheric changes
