The correct answer is: D) excited
A molecule is in an excited state when its energy level is higher than the ground state. That molecule stays in excited state for short time and then returns to a state with lower energy. This return to a lower energy level is described as decay and is the inverse process of excitation.
The transition from ground to excited state of an atom is possible if electrons gain energy that is higher than the difference in energies between the two energy orbits.
Prokaryotic cells don't have a nucleus
Darwin's "Origin of Species" and Lamark's "Theory of Inherited Characteristics"
Answer:
Orchids have some unique features which help them in the evolutionary race. They produce masses of pollen (which improves the chances of pollination), very light seeds (which makes them easier to spread) and can grow on other plants using them to support their own growth.