The answer is D. Food Threshold is the amount of food capable on feeding the organisms.
Answer: Mechanical Isolation
Explanation:
Mechanical isolation is a type of barrier that prevents the species that are closely related from mating with each other.
It is used in case of plants and animals(here beetles) in which the without compatible sex organs individual of different species will not be able to mate and produce offspring.
Thus, the correct answer is option C
Answer: population increases by 15
Explanation:
The population growth will be calculated by adding the Natural Increase in population plus the Net In-Migration. This will be:
Natural increase = Birth - Death rate
= 35 - 7
= 28
Net-In-Migration = Immigration - Emigration
= 4 - 17
= -13
Therefore, population growth will be:
= 28 - 13
= 15
Therefore, population increases by 15