Answer:
C. capillaries connect arteries and veins.
Explanation:
A is false, veins carry blood towards the heart.
B is false because arteries are the thickest blood vessel.
C is completely true
D is false, heartbeat is controlled by electric impulses
The answer is a pathogen
If this answered help you then please consider marking it as brainliest to help me level up to expert

velocity is a vector so it has a magnitude and direction so the answer would be B
Temperature, pressure and composition.