Wich reaction is exothermic

Which element forms the basis of all organic organisms a carbon b oxygen c hydrogen d nitrogen

The bacteria inside a tube worm would be analogous to what organism in the ocean ecosystem near the waters surface? a. photosynthetic algae b. shrimp c. clown fish d. parasitic lamprey

Select the correct answer.what is the observable characteristic of a person called? o a. genotypephenotypeoc.alleleo d.gene