Changes depending on the gravity
Answer:
Arteries carry oxygenated blood away from the heart. Veins carry the blood back to the heart. Veins contain valves that ensure blood flows in only one direction. Arteries don’t require valves because pressure from the heart is so strong that blood is only able to flow in one direction.
Explanation:
The total amount of sea ice showed a decline from 2012 to 2019. The correct option would be D.
<h3>Graphical illustration</h3>
Looking at the graph, from February to June 2012, there is a decline in the amount of sea ice.
A similar decline in the amount of sea ice can be observed in the year 2019.
However, the sea ice levels for the various months in 2012 remain generally above the sea ice levels in the various months in 2019.
Thus, overall, one can say there is a general decline in the ice level from 2012 to 2019.
More on graphical illustrations can be found here: brainly.com/question/21376268
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