This is true because 6 and 15’s sum is 21.
More buildings and more space for humans to move around
A: A command economy<span> is one in which a centralized government controls the means of production. ... There are </span>advantages<span> and disadvantages of </span>command economy<span> structures. </span>Command economy advantages<span> include low levels of inequality and unemployment and the common good replacing profit as the primary incentive of production.</span>
The migration of the Moon away from the Earth is mainly due to the action of the Earth's tides. The Moon is kept in orbit by the gravitational force that the Earth exerts on it, but the Moon also exerts a gravitational force on our planet and this causes the movement of the Earth's oceans to form a tidal bulge.