Fill in the blank: aspirin relieves a headache by blocking in the part of the brain that tells us we are feeling pain.
a. reflexes
b. dendrites
c. stimulants

Which blood cell spend most of their time in the lymphatic system?

'which of these statements about the scientific method is not true? all experiments must follow the same number of steps in the procedure. experiments may be repeated several times. some unexpected results can be beneficial. experimental results may or may not support the hypothesis.

Chloroplasts and bacteria are in size. a. similar b. at different ends of the size range c. exactly the same d. none of these