By what procress does the nephron reclaim na+ ions?

The answer is active transport. This is because the concentration of sodium ions in the blood will be higher than in the filtrate in the collecting tubes hence energy is required to transport the ions against the concentration gradient. This is important in maintaining electrolyte homeostatic balance in the blood. Aldosterone is the hormone that regulates the rate at which reabsorption of na+ ions occurs.

answer; polycythemia is the correct answer;

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