What does it mean when some psychologists support the idea that people experience a series of independent steps or stages?

People want to be independent and they try to remain independent because it makes people feel like they have more control in their lives that is why it starts in stages of for example choosing your own clothes or outfit as a child and will eventually grow into moving out of your parent's house and living on your own. 

Hope this helps!

Be by his side : ) make him feel better

Bmust be the answer, as technically all organs move, so a is incorrect. all organs are made of different types of cells, so that isn’t a problem, so c is also incorrect. human hearts are very similar to many other animals’ hearts, so d is also incorrect, yet the heart is made of muscle, which is hard to grow in the lab so it would be correct to say b