The following are physics questions. It is a part one and two. I tried it myself but kept getting it incorrect for both. I appreciate in advance. Thank you

part 1 of 2 A nerve impulse is propagated across a synapse when the neurotransmitter acetyl- choline is released from the pre-synaptic mem- brane and diffuses across the 28 nm wide synaptic cleft to the post-synaptic membrane. How long does it take a nerve signal to cross a synapse? You can assume that the synap- tic fluid is essentially water and the Diffusion coefficient is D = 4 10-10 m/s. Answer in units of s. Your response... Previous Responses X #1.0.0857 X #2. 0.49x10^-6 s X #3. 2.33*10^-7 PALETTE part 2 of 2 What is the effective speed of transmission? Answer in units of m/s. Your response... Previous Responses X #1. 0.0571 X #2.0.12 PALETTE