The energy levels of an atom are occupied by _. a.
electrons
c.
neutrons
b.
protons
d.
ions

please help!
Please select the best answer from the choices provided

A
B
C
D

In addition to seeds, which of the following characteristics are unique to the seed-producing plants? a) sporopollenin b) lignin present in cell walls c) pollen d) use of air currents as a dispersal agent e) megaphylls

The green colored pigment in chloroplasts is? a. nitrogen b. chlorophyll c. chlorophorm d. chlorofloromethane

Which statement describes a way in which the digestive and excretory systems work together? a. the nephrons absorb nutrients from food going to the large intestine. b. the excretory system balances blood gases in the small intestine. c. the intestinal villi filter blood and send wastes to the bladder. d. the excretory system balances the salts and water obtained from digested food