Why is it necessary for Vibrio vulnificus to turn on different genes when the microbe invades a human

Please see below  

Explanation:

Vibrio vulnificus is a gram negative pathogen. It is usually present at the junction between salt water and freshwater. When it invades a human, this is a new type of host for this virus, as opposed to its previous host - a shellfish. So in order to survive and reproduce inside of the human host, it must activate the genes that will enable it to do so.  

D. Her walking routine

Explanation:

Carol eats 800 kilocalories a day to lose weight. She is 60 years old. Carol has been walking briskly 60 minutes daily for the past 2 months. In her younger days she lifted weights, but she has lost considerable lean body mass over the years because of inactivity. Her walking routine  will increases Carol's energy output and promotes weight loss