The key characteristic of a benign tumor is that such a tumor ...

[Wadzanai]

The key characteristic of a benign tumor is that such a tumor
 
  a. cannot cause brain damage.
  b. does not require surgery.
  c. has a distinct border.
  d. spreads rapidly through infiltration of adjacent tissue.
  e. mostly arises from neuron cell types.

Question 2

The key characteristic of a malignant tumor is that such a tumor
 
  a. does not require surgery.
  b. cannot cause brain damage.
  c. has a distinct border.
  d. spreads rapidly through infiltration of adjacent tissue.
  e. can give off cancerous cells that in turn reach distant sites.

[Silverbeard98]

Answer to Question 1

Answer: c. has a distinct border.

Answer to Question 2

Answer: e. can give off cancerous cells that in turn reach distant sites.

[Wadzanai]

Excellent

[matt95]

Great answer, keep it coming