What component of earth’s atmosphere exists entirely as a result of photosynthesis? a)oxygen gas b)water vapor c)nitrogen gas d)carbon dioxide gas

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons

All ova contain sex chromosomes corresponding to: x y xx xy

Which genetic disorders, caused by an extra x chromosome (xxy), is characterized by a lack of testicular development in males, effeminate features, possible mental impairment, and a thin stature?