The world's population has been growing exponentially. some scientists consider the effects of human population growth a tragedy of the commons. what is the common resource in this example? a. privately owned land b. planet earth c. the sun and moon d. the human population

The correct answer is option B, Planet Earth

Reason-

Here the world common is used to represent the planet earth and all the resources which are present on it. The world population has reached a mark of 7 billion which is putting excessive burden on the existing resources of planet earth be it air, water, land etc, Since the existing and limiting resources are getting exhausted, the planet earth is getting stressed. Since the planet earth is getting stressed all its resources including the human population itself  is at the verge of a tragedy.

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.