Which one is correct for the logistic model of population growth?
$I.$ Population growth rate increases as the size of the population approaches the carrying capacity.
$II.$ All individuals have the same effect on population growth.
$III.$ There are unlimited natural resources.
$IV.$ As population increases,the competition goes on increasing.
Select the correct combination.

$A$ population of $Paramecium$ $caudatum$ was grown in a culture medium. After $5$ days,the culture medium became overcrowded with $Paramecium$ and had depleted nutrients. What will happen to the population,and what type of growth curve will the population attain? Describe the growth curve.

The intrinsic rate of natural increase $(r)$ for the flour beetle is:

Which of the following is not correct with reference to the exponential growth model?

$I.$ 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.

Give scientific reasons: When a plant culture is grown in a limited amount of nutrient medium,growth is slow in the initial stage (lag phase). It increases rapidly in the exponential phase and again slows down in the stationary phase.