$A$ population of $500$ experiences $55$ births and $5$ deaths during a one-year period. What is the reproductive rate for the population during the one-year period?

Which model is considered a more realistic one?

The cause of zero growth of population is

$I.$ 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.

Two opposite forces operate in the growth and development of every population. One of them relates to the ability to reproduce at a given rate. The force opposite to it is called:

Comment on the growth curve given below.