Why do proteins not pass through plasma membranes

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.

Explain how scientists use geologic time to determine the age of landforms.

Why are common names a problem for scientist?