Refers to the number and variety of species on earth.
a. ecology
b. biodiversity
c. humanities
d. ecosystem

Its biodiversity because its the variety of life in the world or in a particular habitat or ecosystem.

The main role of dna in the  cell is the long-term storage of information. it is often compared to a blueprint, since it contains the instructions to construct other components of the  cell, such as  proteins  and rna molecules.the main function of rna is to carry information of amino acid sequence from the genes to where  proteins  are assembled on  ribosomes  in the  cytoplasm. mark brainliest, my work is good.

It's either -limiting factors or -scarce resources but i'd go with my first answer since the food and water are abundant they really aren't scarce