the neighborhood kids are walking around with common pins and sewing needles stuck through their fingertips. there is no visible bleeding. what tissue layer have they pierced?

Communication. releasing emotions/feelings to someone you know you can count on. ; ) someone who may not understand but willing to listen.

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

They need to contract and relax