What organ is it?
it´s the kidneys
What is bigger: veins or capillaries?
Veins are bigger than capillaries.
Does our heart stop when we sleep?
No
What body system is it?
It´s the circulatory system.
Where does blood go in the body?
The blood goes from the heart to the organs.
What organ is it?
It´s the bladder.
What body system is it?
It´s the excretory system.
What organ is this?
It´s the heart.