Answer:
D 1,400
Explanation:
Species A doubles every 2 days and species B doubles every 5 days, so in 10 days, species A will double 10/2 = 5 times and species B will double 10/5=2 times. After 10 days from an initial population of 50 in each species, species A will have 50 x 2 ^5= 50 x 32 = 1,600 population while species B will have 50 x 2 ^2 = 200 population. Their difference is 1,600-200 = 1,400.