The communities plus abiotic and biotic surroundings is called an ecosystem
The well - designed experiment test one factor at a time. The answer to the question above is letter A. 1. The items that are being tested are the independent variables and that they cause the dependent variables to change.
Number 2 but I am not sure sorry dude
DNA
Nucleic Acids are the basis for the storage and transmission of hereditary information in all cells. Determines a cell's function and manufactures proteins & enzymes. Encodes instructions for making proteins and RNA. DNA stores the “operating instructions” for a cell.