This drawing shows the internal anatomy of a sponge. What does the arrow in the middle represent?

A. the direction of the sponge's travel through the water

B. the path sperm take to fertilize the egg of a sponge

C. the flow of water through the body of a sponge

D. the path food takes through the digestive system of a sponge

Enzyme make a hormone as a catalyst

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later