Scientists believe that the Grand Canyon was once covered by ocean
According to the article, jellyfish are invading the oceans near JAPAN. Fisherman in the area assert that the amount of fish and jellyfish in the waters have shifted drastically during their lifetime. There is a large abundance of jellyfish (making it difficult or impossible to fish some days) and a small number of other kinds of fish.
Humans may have caused this problem by over-fishing disrupting the balance of the underwater ecosystem. Jellyfish are eaten by some fish and compete with other species of fish. Also humans building docks, bridges, and other water infrastructures have led to a decline in habitat availability for jellyfish.
A cold front<span> is the transition zone where a </span>cold<span> air mass is replacing a warmer one
</span>T<span>hey move more slowly than warm fronts.</span>
Because other three are characteristics of the cold front and they move faster than warm
so option D is correct
hope it helps