Answer:
c. Observational studies have both independent and dependent variables.
d. Observational studies can be used to test hypothesis.
Explanation:
Observational studies are ones in which a researcher makes observations about his thoughts and views. He observes the risk and other effects before actual test takes place. This is usually the initial phase of research where observations are made for suitability of certain things that are to be researched. There is initial feasibility test conducted to identify whether the further research process is beneficial or not.
<span>this causes some bias, because people without phones cannot be in the sample</span>
Answer:
The executive branch of the U.S. government is responsible for enforcing laws; its power is vested in the President. The President acts as both the head of state and commander-in-chief of the armed forces. Independent federal agencies are tasked with enforcing the laws enacted by Congress.
The correct answer is letter D
Adrenaline is a hormone produced by the adrenal glands and prepares the body to perform physical activities and physical efforts. Adrenaline, or epinephrine, is a hormone and also a neurotransmitter, as it acts on the sympathetic nervous system.
