Answer:
B
Explanation:
The circulatory system is a network consisting of blood, blood vessels, and the heart. This network supplies tissues in the body with oxygen and other nutrients, transports hormones, and removes unnecessary waste products.
The correct answer would be D.
After many generations, only those with genes suitable to live in harsh environments can live. These genes are passed onto their offspring and then we see a rise in antibiotic resistant strains of bacteria such as Methicillin Resistant Staphylococcus Aureus (MRSA).
