Cold water<span> has a higher density than warm </span>water<span>. </span>Water<span> gets colder with depth because cold, salty </span>ocean water<span> sinks to the bottom of the </span>ocean<span> basins below the less </span>dense<span> warmer </span>water<span> near the surface.</span>
Answer:protection from other predators.
Explanation: the quills will stick into a predator that attack the porcupine Note: it does NOT shoot its quills
Asthma is a condition which is characterized by
attacks of difficult breathing and wheezing.
<span>It is a condition related to lung disease in
which there is inflammation in bronchial tubes they become narrow, bronchial
tubes are the passageway through which air enters and leave the lungs. So when
it becomes narrow, it causes difficulty in breathing and sometimes it causes
severe attacks.</span>
