Answer:
a: cooperative.
b: competitive.
c: cooperative.
d: competitive.
Step-by-step explanation:
The rate of change:
dx/dt
gives information about how the quantity x changes as a function of time.
If dx/dt > 0, the population x increases as the time passes.
if dx/dt < 0, the population x decreases as the time passes.
Now, let's analyze the options:
a) dx/dt= -5x + 2xy
in this case, x represents one population and y represents the other population. Where x and y should only be positive numbers because we can not have a negative population.
Notice that in this case, if y increases, then dx/dt increases.
Then we have cooperative species because the population y helps the growth of population x.
b) dx/dt = 4*x - 2*x*y
Similar to the previous case, but now as the value of y increases, the value of dx/dt decreases, then we have competitive species.
c) dy/dy = -4*y + 3*x*y
Notice that now we have the rate of change of y, in the right side, we can see that as x increases, also the rate of change dy/dt.
Then the population x helps to increase the population y, which means that the species are cooperative.
d) dy/dt = 2*y - x*y
Now as x increases, the value of dy/dt decreases, then these species are competitive.
