High growth at the time of the exponential phase of the human population growth curve is due to:

In nature, a given habitat has enough resources to support a maximum possible number, beyond which no further growth is possible. This characteristic feature of nature is known as

Populations evolve to maximize their reproductive fitness,also called Darwinian fitness,with:

From the given graph of population growth,select the correct option that shows the correct value of '$r$' and the corresponding age pyramid.

$I.$ Populations evolve to maximize their reproductive fitness,also called Darwinian reproductive fitness (higher $r$ value),in the habitat in which they live.
$II.$ The population growth rate $r$ is inversely related to generation time.
$III.$ The housefly,which has a short life span and produces a large number of eggs,could be considered as a '$K$' selected species.
$IV.$ Under a particular set of selection pressures,organisms evolve towards the most efficient reproductive strategies.
$V.$ Life history traits of organisms have evolved in relation to the constraints imposed by biotic and abiotic factors in their habitat.
Select the combination of correct statements.

What is the formula for exponential population growth?