Three Weeks After Conception, Which of the Following Has Happened

Question

Three weeks after conception, which of the following has happened in an embryo?
A) organ formation
B) neural tube formation
C) limb bud formation
D) primitive eye formation

Accepted Answer

By three weeks after conception, the neural tube begins to form in the embryo, which will eventually develop into the brain and spinal cord. Organ formation, limb bud formation, and primitive eye formation typically occur later in fetal development.