A simple example is a connection between the circulatory and respiratory systems. <span>As </span>blood<span> circulates through your body, it eventually needs fresh oxygen </span><span>from the air. When the </span>blood<span> reaches the lungs, part of the </span>respiratory system<span>, the </span>blood<span> is re-oxygenated.</span>
<span>What substances will make salt when combined</span>
Answer:
it prevents for things to go in and out of it, kinda like a cell membrane.
A scientific theory is a well-tested explanation for a wide range of observations or experimental results. A hypothesis is a possible answer to a question.
