Answer:
d. 749
Step-by-step explanation:
To calculate the number of newborns (N) in an insect population using the equation N=rI−bI2, where r and b are variables, given that: 
r=1.5, b=0.0015, and number of adult insects (I) = 500. 
Solve for N in the equation by substituting for r, b and I with the values given. 
Number of newborns (N) = rI−bI2 
 = (1.5 × 500) - (0.0015 × 500 × 2) 
 = 750 - 1.5 
 N = 748.5 
Rounding up to the nearest whole number, N = 749 
749 newborn insects were represented by N