Answer:
B. Neurons are cells that conduct electrical impulses.
Explanation:
Red blood cells carry oxygen throughout the body. White blood cells protect against pathogens and aid in blood clotting after injury. Blood cells cannot contract.
Neurons generate and conduct electrical impulses. So this one is correct.
Epithelial cells line the cavities and surfaces of blood vessels and organs, protect underlying tissue, regulate the exchange of chemicals, and secrete various substances. They do not react to stimuli, however neurons do.
Smooth muscles helps the skeleton move, smooth muscle is found in blood vessels and some organs, and cardiac muscle helps the heart beat and pump blood. They are however, not components of blood.
Answer:
D
Explanation:
Carbon is expelled not used for producing sugars or any of that
Answer:
An experiment imposes treatment on the subjects, but an observational study does not
Explanation:
Observational studies are research studies in which an effect, process behaviour etc. are observed, without any change. For example, observation of the possible effect of a treatment on subjects.
On the other hand, experimental studies are studies in which the treatment is included. Experimental studies are randomized, meaning that subjects that are in experiment are randomly put to a treated group or a control group.
This a tough one, and technically they all have to do with an authoritative body enforcing an environmental policy. But the most specific ones of them all would be the first sentence and the last two sentences.
