Describe physical developments that occur in infants between birth and their first birthday.

After the birth infants are not able to control their body and movement.  The movements that occur are nothing but the reflexes as their nervous system is not developed completely. Around the first month, the infants start seeing objects that are around 10 inches away from their eyes. Clear vision comes around at the age of six months.  

Around the age of four months, infants or babies start to show some muscle control and nervous system as they can hold their heads up and starting to sit on their own support. At the age of five months, babies begin to roll over.

After six months of birth, babies start to eat at a regular time and sleep at a particular time. They start to hold things like a spoon. Crawling with stomach touching the floor is also notices in normal cases. At the age of eight months they use their thumb to hold things and try to stand up by support. By the age of a year weight and height in thrice and inch per month respectively in comparison to the birth weight and height.