I can help with the first one and third for you.
Symbol | atomic # | Mass of # | # of Protons | # of electrons | # of neutrons
Na | 11 | 23 (when rounded) | 11 | 11 | 12
Sr | 38 | 88 (when rounded) | 38 | 38 | 50
(sorry if this didn't help)
Food webs with fewer species are more sensitive to the loss of species and ecosystem disturbances
Genes are heredity that are transferred from a parent to offspring and determine a physical or mental characteristic for the offspring
I guess it would have to be A
