in the nephron loop ion pumps, which respond to aldosterone, exist. two-thirds of the sodium and chloride ions remaining in the tubular fluid are reabsorbed. reabsorption of ions, amino acids, water, and other organic nutrients is its primary function. final adjustments are made in the composition and concentration of the tubular fluid. active secretion of acids, ammonia, and drugs occurs.

Which of the following statements is most likely correct about a rock belonging to the jurassic age and a rock belonging to the cambrian age? options: 1) they have identical fossils of organisms that have evolved over time. 2) both have animal fossils preserved in them due to weathering and erosion. 3) they contain different fossils because life on earth has changed through time. 4) the fossils in them were formed on the surface of earth due to exposure to sunlight.