  This paper addresses null controllability for both forward and backward
linear stochastic parabolic equations by introducing convection terms on the
drift parts with bounded coefficients. Moreover, the forward stochastic
parabolic equation includes a convection term on the diffusion part. The null
controllability results rely on novel Carleman estimates for both backward and
forward stochastic parabolic equations, encompassing a divergence source term
interpreted in the weak sense. These Carleman estimates are established through
the application of the duality technique. In doing so, we resolve some
previously unanswered questions (see Remarks 2.1-2.2 in [S. Tang, and X. Zhang,
SIAM J. Control Optim., 48 (2009), p.p 2191-2216]). Additionally, we present a
more accurate estimation of the null-control costs.
