The correct answer is H+.
<span>Secretion from the peritubular capillary network into the convoluted tubules is a process called tubular secretion. This is an important process for both waste removal and acid-base balance. The secretion step is usually used to remove drugs, toxins, and poisons, or other molecules such as potassium (K+) and hydrogen (H+). The secreted molecules come from the peritubular capillaries and pass through the interstitial fluid before going through the wall of the tubule into the lumen of the tubule.</span>
Answer:
Homologous structures can be described as the structures which are similar to one another present in different organisms. These similarities depict that the organisms might have a common ancestor i the past. For example, the forelimb of man, birds, dogs.
Analogous structures can be described as structures in different organisms which perform the same function but might not have a common origin. For example, the wings of bats and birds.