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

During the lag phase of the population growth curve,there is very little growth due to:

When the reactions are not growth limiting,the growth curve is . . . . . . .

The formula for exponential population growth is $:-$

The statement 'Food supply increases in an arithmetic progression,while population tends to increase in a geometric progression' was proposed by:

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