<prompt> Zygote with zona pellucida reaches uterine cavity by-2 days4 days5 days6 days  <response>: Ans-B lets revise some imp points:- 1-morula16 cell stage 2-blastocyst hatchingZP removalimplantation5-12 days after fertiization5-7 days 3-sequence of reactions is alphabeticalacrosome rxn fb cortical rxn fb zona reaction. 4-conceptus reaches uterine cavity in 32cell stage. 5-transvaginal insertion of coceptus 8 cell stage. 6- spermatogenesis is completed in 74 days 7-trophoblast differentiates into cyto and syncytio day 6. 8- ovulation occurs 10-12 hrs before LH PEAK. 9-LH SURRGE occurs 34-36 hrs before ovulation. 