Solution: The correct answer is A.
After introducing the idea of fluid homeostasis, which is obtained by balancing hydrostatic and osmotic pressures, the question asks the examinee to predict the consequences of a blood clot on the venous side of a capillary bed. To answer this, it is necessary to know that blood flows from arteries to capillaries and then to veins. If flow is blocked at the venous side, blood would accumulate in the capillaries. Thus, hydrostatic pressure would build up in the capillaries, causing a net increase in fluid flow into the interstitial spaces. A is therefore correct. B is incorrect because there will be an increase in net fluid flow into the interstitial spaces, not a decrease. C is not the best answer because the increase in osmotic pressure in the capillaries would be an indirect result of the fluid flow out of the capillaries. D is incorrect because the flow of fluid out of the capillaries would slightly increase, not decrease, the osmotic pressure. Thus, A is the best answer.
Solution: The correct answer is C.
The development of incomplete embryos, described in choice A, falsifies the Regulative Hypothesis. Answer choice B states that the fate of a cell depends on its own internal factors, but this would be true whether the Mosaic Hypothesis or the Regulative Hypothesis was true. Cells must have genes to guide their fate. The question is whether they have a full complement of the organism's genes or just a part. Answer choice D restates the Mosaic Hypothesis, that genes are distributed unevenly to daughter cells during development. Answer choice C, the correct answer, however, supports the Regulative Hypothesis. If all cells contain identical information for construction of the organism, then some external factor must tell different parts what they should become. If specific courses of development were shown to be dependent on the position of the cell in the embryo, it would explain this aspect of the Regulative Hypothesis. By supplying an answer to the question of how the parts of an animal develop differently when they have the same genes, that information buttresses the Regulative Hypothesis. Thus, answer choice C is the best answer.