i am so sorry im taking up the answer spot but i have to say the answer is not d im not sure what it is but its not d!
The Arrival of the Europeans has been studied and proven to be the reason for the decline in the Native American population. About 500 years ago when Columbus Arrived in the Americas is when the decline started. From the transportation of diseases and common cold, to the wars fought over land, the population received it's biggest decrease after the arrival the foreigners.
Answer:
the circulatory system transports oxygen throughout the body via blood cells and the respiratory system takes in oxygen into your lungs through your bronci to your alveoli which then diffuses the oxygen into the deoyxgenized blood cells .without the respiratory system the circulatory system wouldn't work the need to be in tandem in order for to stay alive.
<span>invest tax revenues in items such as highways and education</span>