Penguins can't fly but still have streamlined body why

Most animal cells membranes have proteins that pump ions out of the cell and potassium ions into the cell

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

How does the carbon cycle involve an exchange of carbon