Why is about half of all freshwater on Earth is inaccessible to humans? Group of answer choices

It is too deep underground

It is in the atmosphere in clouds

It is too dirty to clean

It is frozen in glaciers

Several billion years ago which gas was the least prevailant in the atmosphere

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. what is the significance of this finding? it will be important to include cysteine in the diet of the mice. cysteine residues are required for the formation of α helices and β pleated sheets. cysteine residues are involved in disulfide bridges that form tertiary structure. cysteine causes bends, or angles, to occur in the tertiary structure of proteins.

Imagine that you are searching your room for a textbook. which portion of the cortex would be most active during this search?