Let $w$ be the number of worms (in millions) and $r$ the number of robins (in thousands) living on an island. Suppose $w$ and $r$ satisfy the following differential equations, which correspond to the slope field shown below. $$\frac{dw}{dt} = w - wr, \qquad \frac{dr}{dt}=-r+wr.$$

Assume $w=1$ and $r=3$ when $t=0$.
Does the number of worms increase, decrease, or stay the same at first? ? increases decreases stays the same
Does the number of robins increase, decrease, or stay the same at first? ? increases decreases stays the same

What happens in the long run?
? w and r both go to zero w goes to zero and r increases to infinity w increases to infinity and r goes to zero w and r both go to stable long-term values w and r oscillate