Practice question

Question

Given below are statements about development in d ifferent model organisms A. Xenopus egg has yolk and hence undergoes meroblastic cleavage. B. Embryonically transcribed beta-catenin in the blastomeres of sea urchin embryos regulates the autonomous specification of micromeres. C. The sodium pump activity in the trophoblast helps in the formation of blastocoel of a mammalian blastocyst. D. Prevention of tubal pregnancy is one of the major functions of zona pellucida in humans. Which combination of the statements is true?