Asked for female, 33 years old from Aurangabad
5 month old baby neither sits nor stands. When you hold her up to. Make her stand, she will flex her legs and draw it up to avoid touching it to ground. The brain connections are yet to develop.
There is no relation between formula feeding and development.
Don't compare your baby and it's development with others as each baby is unique and if you keep comparing then it might increase your anxiety than helping it in any way.