Why are rice and dals not washed repeatedly?

Sita has learned to eat rice and dal with her hand. When she is given dal and rice, she mixes rice and dal and starts eating. She has ........ eating rice and dal into her schema for doing things.

Sita has learned to eat rice and dal with her hand by seeing another girl doing the same. Which principle of development is it associated with?

Why is it essential to wash the precipitate with water before estimating it quantitatively?

A hard wire is broken by bending repeatedly in alternating directions. Why ?