Which characteristic is common to both unicellular and multicellular algae?
a) presence of a flagella for locomation
b) presence of chlorophyll a for carrying out photosynthesis
c) cell walls made of cellulose

Why are carbon dioxide concentrations expected to increase? a carbon dioxide concentrations are expected to increase, because fossil fuel burning is expected to increase b. carbon dioxide concentrations are expected to increase, because of an increase in agriculture. c. carbon dioxide concentrations are expected to increase, because more land will have to be cleared for increasing populations and agricultural use. d. all of the above select the best answer from the choices provided mark this and return save and exit next submit submit