Question

1. the nervous system consists of two main divisions: the central nervous system (cns) and the peripheral nervous system (pns). the cns consists of: a) sensory and motor neurons b) blood vessels c) the brain and spinal cord d) all the nerves in the body 16. which organs collaborate to provide nutrients to cells and eliminate cellular waste in our bloodstream? a) pancreas and kidneys b) heart and small intestine c) lungs and esophagus d) brain and mouth 17. what is the primary function of sensory organs in the nervous system? a) to perceive the environment b) to regulate body temperature c) to carry out a response d) to initiate muscle contractions 18. what is the primary function of nephrons in the kidneys? a) blood transportation b) digesting food c) filtration and waste removal in the blood d) temperature regulation 19. which of the following is true about bacteria but not viruses? a. they contain dna b. they can reproduce without a host c. they always cause disease d. they are smaller than viruses 20. which is true about viruses? a. they are living cells b. they must infect a host to reproduce c. they have cell walls d. they can be killed by antibiotics 21. what is the main function of the cell membrane? a. produce energy b. control what enters and leaves the cell c. make proteins

Explanation:

1. The central nervous system (CNS) is composed of the brain and spinal cord. Sensory and motor neurons are part of the peripheral nervous system (PNS). Blood vessels are not part of the CNS. All the nerves in the body refer to the PNS.
2. The heart pumps blood, and the small intestine absorbs nutrients. The pancreas and kidneys are mainly for digestion and waste removal. Lungs are for gas exchange, esophagus for food transport. Brain and mouth have different functions.
3. Sensory organs detect stimuli from the environment. Regulating body temperature is not their main function. Carrying out a response is done by effectors. Initiating muscle contractions is not their primary role.
4. Nephrons filter blood and remove waste. Blood transportation is done by blood vessels. Digesting food is the role of digestive organs. Temperature regulation is not their function.
5. Bacteria can reproduce without a host (binary fission), while viruses need a host. Both can contain DNA. Not all bacteria cause disease. Viruses are generally smaller than bacteria.
6. Viruses are not living cells. They must infect a host to reproduce. They do not have cell walls. Antibiotics do not kill viruses.
7. The cell membrane controls the movement of substances in and out of the cell. Producing energy is done by mitochondria. Making proteins is the role of ribosomes.

Answer:

1. C. The brain and spinal cord
2. B. Heart and small intestine
3. A. To perceive the environment
4. C. Filtration and waste removal in the blood
5. B. They can reproduce without a host
6. B. They must infect a host to reproduce
7. B. Control what enters and leaves the cell