The kidneys maintain our body's water balance by controlling the water concentration of blood plasma. The kidneys also control salt levels and the excretion of urea. Water that is not put back into the blood is excreted in our urine.
The excerpt is from Of Plymouth Plantation, the journal by William Bradford who was the governor of Plymouth Colony in 17th century. It is the description of Bradford's account on the Indians named Squanto and Samoset and how they helped the Pilgrims to negotiate with Indian tribe chief. The excerpt shows that the Europeans were strangers for the Indians until the writing recalls the story of two aforementioned characters. They didn't understand the Europeans first and they were somehow trying to be careful. Therefore, the correct options are guarded and wary.
