Cepheids: brighten and dim periodically
can be used to measure stellar distance
have been discovered in galaxies other than our own
all of the above

During the day, plants produce by splitting water molecules in the light-dependent reactions of photosynthesis. at the same time, plants use cellular respiration to produce some of the needed by the light-independent reactions to make sugars. during the night, plants produce because takes place.

What are the two functions of the respiratory system

Explain the difference between mutations in sex cell and those in somatic cells