Biology Questions
Explore questions in the Biology category that you can ask Spark.E!
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