<span>Calcium<span> is the element responsible for most of the material found in teeth.
Calcium plays a vital role in the formation and maintenance of healthy teeth and gums. Calcium makes the jawbones healthy and strong in order to hold the teeth in place.
Dairy foods such as cheese and yogurt, beans, cabbage and brown rice are good sources of calcium.</span></span>
I think its C. global warming
because the other one directly threats aquatic bio diversity while global warming doesn't just affect aquatic biodiversity
Answer:
<u><em>Active Transport</em></u>
Explanation:
<u><em>active transport
</em></u>
During <u><em>active transport</em></u>, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy (usually in the form of ATP). It is the opposite of passive transport.
