Which elements are present in all organic compounds Hydrogen and oxygen
Nitrogen and oxygen
Nitrogen and hydrogen
Hydrogen and carbon

Answers to mastering biology drag the labels to their appropriate locations to complete the punnett squares for morgan's reciprocal cross. drag blue labels onto the blue targets to indicate the genotypes of the parents and offspring. drag pink labels onto the pink targets to indicate the genetic makeup of the gametes (sperm and egg). labels can be used once, more than once, or not at all. hints