thylakoids
Chloroplasts contain saclike photosynthetic membranes called thylakoids, which are interconnected and arranged in stacks known as grana. Pigments are located in the thylakoid membranes. The fluid portion outside of the thylakoids is known as the stroma.
Struggled with this earlier but because of the high altitude only some animals can live there and thrive because of the lower oxygen levels
'Red shift' is a key concept for astronomers. The term can be understood literally - the wavelength of the light is stretched, so the light is seen as 'shifted' towards the red part of the spectrum.
Hope this helps.
