Element or compound help

What is an endocrine function? (apex) a. esophageal glands release mucus into the esophagus b. salivary glands release saliva into mouth c. swear glands release sweat to the skin d. the pineal gland releases melatonin into the bloodstream

The term equestrian relates to which animal? bulls cows horses pigs

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?