The correct answer is the organ.
The multicellular species are formed of various parts, which are required for survival. These parts are differentiated into the levels of the organization. There are five different levels, which are named as cells, tissue, organs, organ systems, and organisms.
When two or more layers of tissue function together, they produce an organ. All the animals comprise vital organs, without which they cannot survive. These include the kidneys, liver, lungs, brain, and heart.
Oxygen in the presence of sunlight
The travel to the galciers is something one can never forget. The aura of the place along with the beauty that one gets to notice is so enriching to entice one to stay there forever. The glaciers are one of the many natural wonders our world has to offer. Formed because of the accumulation of the snow year after year, these glaciers are present in many sizes. Besides, the movement of the glaciers, such as the glacial erosion and deposition leads to the formation of many other attractive features, such as the corries, pyramidal peaks, truncated spurs, and hanging valleys. You must definitely visit these places to give your soul this exciting experience.
A - rostral and cranial are very similar but rostral are for head structures
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