Secretion into the tubular fluid occurs when principle cells in the pct secrete h+ into the urine when the principle cells in the dct and collecting ducts reabsorb na+ and secrete k+ when the cells in the loop of henle become impermeable to water never occurs at all

answer

crater lake was formed when mount mazama produced a large eruption and collapsed to form a caldera, which then filled with water forming a lake.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands