4. Electrons move in (1) , and (2) consists of elections in orbitals at the same principal’s energy level. (1) Electron orbitals Principal energy levels An electron shells (2) An electron shell A valence shell An electron shell 10. A buffer maintains a Ph that is which of the following? a. Basic b. Acidic c. Consistent d. Neutral * I think its C.

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

here's your answer.