Phylum: Chordata
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Bubo
Species: B. scandiacus
from species down we have:
species
population
organism
organ system
organ
tissue
cell
organelle
macromolecule
molecule
atom
elementary particle
I hope this helps you.
The correct answer would be D.
After many generations, only those with genes suitable to live in harsh environments can live. These genes are passed onto their offspring and then we see a rise in antibiotic resistant strains of bacteria such as Methicillin Resistant Staphylococcus Aureus (MRSA).
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray Group 2 alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.[5] Free calcium metal is too reactive to occur in nature. Calcium is produced in supernova nucleosynthesis.