Which category of gymnosperms are thought to have given rise to modern-day flowering plants? gnetophytes

ginkgo

conifers

cycads

Although there are a limited number of amino acids many different types of proteins exist because..

Facilitated diffusion move large molecules and/or polar molecules across the cell membrane. what does facilitated diffusion use to do this?

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