Which of the following parameters of the population can be negative?

Environmental resistance includes which of the following factors?

The exponential growth equation is $N_{t} = N_{0}e^{rt}$,where $N_{t}$ is the population density after time $t$. What do $N_{0}$ and $r$ refer to,respectively?

When does the growth rate of a population following the logistic model equal zero? The logistic model is given as $dN/dt = rN(1 - N/K)$.

What is Darwinian fitness?

Which option is correct for curve $a$ and $b$?
| Curve | Equation | Type of Curve |
| :--- | :--- | :--- |
| $a$ | ? | ? |
| $b$ | ? | ? |