Researchers searched for an activator of neural tissue formation. What is the real pathway for this developmental phenomenon? a. Neural tissue formation occurs via BMP inhibition by proteins secreted from the organizer. b. Noggin activates ectoderm to become neural tissue. c. Nodal activation induces mesoderm to make neural tissue. d. Beta-catenin is required for formation of neural tissue.

What part of an infant’s body is said to stay in an immature state until needed to produce more cells? a. uterus b. stem cells c. umbilical cord d. placenta

Use the graphs to answer the question. Which answer describes a logical reason why LH and FSH were chosen for this study?   A. These hormones regulate gametogenesis and sex hormone production, so they play a pivotal role in puberty.   B. These hormones are only present in individuals undergoing puberty, so they provide a good indication of puberty.   C. These hormones directly cause puberty related changes.   D. These hormones are the only ones that fluctuate with puberty while other hormones are unchanged.   Use the graph to answer the question. The graph indicates increases in both FSH and LH for males and females. However, male and female signs of puberty differ. Which of the following explains why?   A. Hormone levels increase for both of them, but LH levels increase more for males and less for females.   B. FSH and LH trigger higher testosterone production in males and higher estrogen production in females.   C. FSH and LH promote a positive feedback…

The embryos of complex multicellular animals must establish spatial coordinates if development is to proceed. An important reference coordinate for developing frogs is theA. location of the vegetal pole.B. location of the animal pole.C. point of sperm penetration.D. location where gastrulation begins.E. direction of the sun.