What type of cancer is studied in the animation and where does it form?

Are you in K12? I did this assignment last week.

The cancer cells proliferate to form mass of cancer cells called a tumor. As the tumor grows larger, it begins to release proteins from
Cell Reproduction Unit
the cell to attract new blood vessel growth, this is called angiogenesis. At this point the tumor contains , 1 million cells and is about the size of a 'bb'.
Tumor cells remain at original site. It can be removed surgically or killed by radiation, usually eliminating any further cancer development at that site.
some tumor cells send out signals that tell the body to produce a new blood vessel at the tumor site. These cells not only have their own food and oxygen supply, they also have an avenue for escape to a new part of the body - through the new blood vessel and into bloodstream. Cells that break away from the tumor begin to spread to surrounding tissues (via the bloodstream or lymph) and start new tumors = metastasis. Usually surgery is performed to remove the tumor, followed by radiation and chemotherapy.  

Really hope this helped, as it helped me :P

The answer would be dogs.