Which of the following would increase the spread of cancer through the body?

low blood-flow rate
low lymph-flow rate
low antibody count
low lymphocyte count

which of the following prevents blood from flowing backward through the circulatory system?

smooth muscle in the arteries
smooth muscle in the veins
valves in the arteries
valves in the veins

1.Low lymphocyte count

Explanation:

Lymphocytes are type of white blood cells. They are important for generating immune response against the disease causing pathogens. When the count of lymphocyte becomes low the body immune system becomes weak which can make the body susceptible to diseases. Cancer is a disease which occurs in the body when the body immune system becomes severely weak. This can be said that cancer results due to low lymphocyte count.

2. Valves in the veins

Explanation: Valves are present in veins which prevents the back flow of blood. This ensures that blood flows only in one direction. Valves are not present in arteries because the flow of blood in arteries is strong and forceful that makes the blood flow in only one direction.

c is the answer to this question. altitude affects the weather because air molecules evaporate.