Answer:
A. The complete journey of one object around another.
Explanation:
Revolution can be defined as the complete journey of one object around another.
This ultimately implies that, the complete movement (motion) of the Earth along a path (an orbit) around the Sun or the Moon around the Earth is referred to as revolution.
Basically, it takes the Earth 365 1/4 days to completely move around the Sun.
Additionally, the earth rotation and revolution gives rise to the following phenomenon;
a. Day and night.
b. Seasons such as summer, winter, autumn, etc.
c. Creation of heat zones and ocean currents
Explanation/Answer:
Among Russia's most important environmental problems: Water pollution is the most serious concern. Less than half of Russia's population has access to safe drinking water. ... Air quality is almost as poor as water quality, with over 200 cities often exceeding Russian pollution limits, and is likely to worsen.
