If ancient volcanoes gave off the same gases, which gas would have been most helpful in the development of early life-forms that could carry out photosynthesis?

Depending on the organism the number of in a cell may change

Which statement describes an endocrine function rather than an exocrine function? a. salivary glands release saliva into the mouth. b. sweat glands release sweat onto the skin c. the pineal gland releases melatonin into the blood. d. esophageal glands release mucus into the esophagus.

2. given that most biochemical (other than coal) rocks react with hydrochloric acid, what does that tell you about organisms?