Answer:
At first, a fetus cannot distinguish between different voices.
A fetus begins responding to sound at between 22 and 24 weeks but can only hear low frequencies, such as a dog barking or a lawn mower.
As the auditory system and the brain continue to develop, this range increases. By late pregnancy, the fetus can hear voices and distinguish between
so at 22 weeks they're in the middle of the second trimester and can hear sounds but in the 3rd trimester can distinguish between voices
So its acquired immunity and the cells responsible are the B lymphocytes that produces antibodies against the virus. Memory is keep since first encounter of the virus by the immune system by way of the antibodies that was initially produced. The antibodies are there already, which makes it fast to act upon when expose again.
Detox. Varies for every individual but most accurate is within a few days to a week
When your baby grunts, it usually means they're learning how to have a bowel movement. They haven't yet figured out how to relax the pelvic floor while also using abdominal pressure to move stool and gas through their system.