1. Using examples, describe three
biology themes

The three major themes in the study of biology are diversity, interdependence, and evolution. Diversity concerns the observation and classification of the many different species of living things on Earth. ... When changes in that balance or in Earth's physical structure occur, species either die off or adapt

c

explanation:

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds