Correct order is: organism, population, community, ecosystem, biosphere.
Answer:
A. Integumentary system
Explanation:
The integumentary system consists of the skin,hair and nail. This system consists of the largest organ in the body. The skin helps in protection against pathogens by shielding the internal body system from external objects.
The skin also helps in Vitamin D production through sunlight.
It also helps to prevent dehydration through regulation of water loss.
Ice is less densw than water (a)
The substances which are less dense than water float on water
