- Twins that occur when blastomeres separate are calledblastulatory.fraternalmonozygotic.dizygotic.zygoblastic.
- In polygenic inheritance, phenotypic characters aredetermined by interactions among several genes.determined by the genes on the Y chromosome.always controlled by genes on the same chromosome.determined by multiple copies of a single gene.determined by a double pair of alleles.
- If an individual carries a pair of alleles that are the same, the individual is ________ for the trait.
- Stretching of the cervix causes an increase in the blood levels ofoxytocin.relaxin.chorionic gonadotropin.progesterone.estrogen.
- The region known as the primitive streak is the site ofendoderm formation.migration of ectodermal cells to form the mesoderm.ectoderm formation.amnion formation.migration of mesodermal cells to form the endoderm.
- If an individual carries two different alleles for the same trait, the individual is ________ for the trait.
- The penetration of the endometrium by the blastocyst is referred to asimplantation.embryogenesis.cleavage.placentation.fertilization.
- The primary nutrient source for early embryonic development that later becomes an important site for blood formation is theumbilical vein.basal decidua.placenta.amniotic fluid.yolk sac.
- Uterine contractions that are irregular and brief that occur toward the end of gestation are calledexpulsion.dilation.true labor.parturition.Braxton-Hicks.
- Which embryonic germ layer forms the linings of the respiratory and digestive tracts?
- During gastrulation,the placenta penetrates the endometrium.three germ layers are formed.the blastomeres fuse.cells from the hypoblast move to the epiblast.the neural tube closes.
- The alternate forms of any one gene are called
- In ________, implantation occurs somewhere other than in the uterus.ectopic pregnancyabortionhydramniosplacenta previaspontaneous abortion
- ________ are nearly identical cells that are produced by early cleavages.BlastomeresBlastulasAmnionsGastrulasMorulas
- A space opens within the inner cell mass that will form theallantois.lacunae.blastocoele.chorion.amniotic cavity.
- If fertilization occurs, the ________ is maintained because the embryo secretes ________.corpus luteum; human chorionic gonadotrophincorpus albicans; placental prolactincorpus albicans; human chorionic gonadotrophincorpus cavernosum; human chorionic gonadotrophincorpus luteum; luteinizing hormone
- Polyspermy results inhaploid individuals.fetuses with different fathers.chimeric adults.twins.a nonfunctional zygote.
- The layer of follicle cells that surround the unfertilized egg is called the
- The ________ is formed by the allantois, blood vessels, and yolk sac.
- Sperm release ________ to break down the bonds between adjacent follicle cells surrounding the oocyte.calciumrelaxinzonal inhibiting proteinsglucosehyaluronidase