The answer is Integumentary System. it is the organ framework that shields the body from different sorts of harm, for example, loss of water or scraped spot from outside. The framework involves the skin and its limbs.
The integumentary system comprises of the skin, hair, nails, organs, and nerves. Its principal work is to go about as a hindrance to shield the body from the outside world. It additionally capacities to hold body liquids, ensure against ailment, dispense with squandering items, and direct body temperature.
C. testable and observable
It would be the first choice :)
Because when replicating DNA, this process is called semi-conservative
Hope this helps :)
~His Cookie Monster
I will go with choice (C) density dependent pattern