7. Which of the following systems is NOT found in a flatworm: a. Digestive system
b. Respiratory system
c. Nervous system
d. All of the above

The vaccine in a flu shot contains weakened flu viruses. how does a flu shot work with the immune system? a. it destroys lymphocytes. b. it destroys macrophages. c. it activates macrophages. d. it activates lymphocytes.

The activity of the modern sample is 1.10 bq . how long does that measurement take?

In 2001, records showed that local stocks of fish were down worldwide. yet, records of harvests indicated that fish were being taken at records rates. what was actually happening?