A) The mesoplankton is 1 x 10^6m x the femtoplankton which is 2 x 10^-8m
So an expression in meters as a product of two numbers in scientific notation for the largest mesoplankton is
(1 x 10^6 x 2 x 10^-8)m
B) Applying the commutative and associative property of multiplication we have
(1 x 10^6 x 2 x 10^-8)m = ((1 x 2 )x (10^6 x 10^-8))m
C) (1x2) (10^6 x 10^-8) = 2 x 10^6+-8 m