What is the difference between a base unit and a derived unit

Describe the function of the endomembrane system? what organelles are involved?

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

Which substance contains thylakoids? a) nadph b)atp c)stroma d)chloroplast