How would planting a variety of plants in a vacant (empty) lot establish an ecosystem in that location?

the plants would grow  and reproduce working together forming nutrients from their dropped  leaves / branches etc causing insects to come along and do the same  along with animals and a keystone species to form a revolving ecosystem continuing an energy moving process

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.

the answer is definitely c.