An example of an ecosystem that benefits people could be the ocean.
The ocean regulates the temperature of the earth, allowing a more comfortable place for people to live.
Hope this helps!
Answer:
Mass does not affect gravity and distance has an indirect relationship.
Explanation:
The equation for gravity is, g = 
where, G = gravitational constant
M = mass of the planet
R = distance between the bodies (object and center of planet)
so, gravity depends on the mass of planet, not on mass of object
and is inversely proportional to sqaure of distance.
The aa genotype should
a*a = 0.4 * 0.4 = 0.16