Answer:
It would be the plant type
Explanation:
This is because you are measuring the growth of 2 different plants, so they can not be the same. all the other options ARE constants
The immune system<span> is made up of a network of cells, tissues, and organs that work together to protect the body. One of the important cells involved are white blood cells, also called leukocytes, which come in two basic types that combine to seek out and destroy disease-causing organisms or substances.</span>
The gene is responsible for the cat's hearing.
Lack of antibodies because thats the stuff to fight things away
