| Which of the following factors increase, the size of a population? |
| a) | Natality and immigration | b) | Natality and mortality |
| c) | Mortality and immigration | d) | Natality and emigration |
| (d)The size of a population for any species are not a static parameter. It keeps changing in time depending on various factors including food availability, predation pressure and adverse weather, water, space, accumulated waste, etc. |