.............................Correct.
Answer:
viruses can make your body sick and your blood cells wouldn't be right so you have to be careful with shots or people ine general
Answer:
D. pituitary gland
~+. lil more info .+~
The circulatory system consists of three independent systems that work together: the heart (cardiovascular), lungs (pulmonary), and arteries, veins, coronary and portal vessels (systemic). The system is responsible for the flow of blood, nutrients, oxygen and other gases, and as well as hormones to and from cells.
The answer is A. Environmental conditions are not always right to produce flowers and seeds for sexual reproduction.
Most plants are able to reproduce either way because even if the conditions aren't right for the plant, it can still make more flowers so it doesn't die out.
I hope this helps! :D