Amother hands her baby a rattle, saying, "here you are." she then gently takes the rattle away, smiling and saying, " you." she does this repeatedly, letting the baby keep the rattle for several seconds each time and encouraging the baby to offer the rattle. eventually, the baby takes the rattle, holds it for a few seconds, and then holds it out to her mother and smiles. this is an example of:

Scaffolding

Explanation:

A mother taking away the rattle from her baby and again giving it back is an educational method called scaffolding which helps her infant in developing and learning things faster. Scaffolding allows the child to become more experienced with the help of his mother in things rather doing it himself.

~kinetic ~potential

explanation:

kinetic and potential energies would be types of mechanical energies.

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."