Males in a population differ in the time they spend displaying to females. A researcher hypothesizes that predators are responsible for these differences. Males display for longer durations when there are no predators in the vicinity and for shorter durations when there is a predator nearby. Which of the following study designs is the most appropriate test of this hypothesis?

#Question id: 7276

#Unit 5. Developmental Biology

The cells that make up a tetrapod limb arise from three developing tissues:

The ____a______ will provide skeletal precursors to the limb.

The _____b____ will provide muscle precursors to the limb.

The _____c____ will provide the skin of the limb.

Which of the following option is correct?

#Question id: 7275

#Unit 5. Developmental Biology

The following experiment is designed to study the role of several hormones in the regulation of metamorphosis in frogs.

If the thyroid gland were removed from the tadpoles in Group 4, metamorphosis would

#Question id: 7274

#Unit 5. Developmental Biology

The following experiment is designed to study the role of several hormones in the regulation of metamorphosis in frogs.

 If the thyroid gland were removed from the tadpoles in Group 3, metamorphosis would

#Question id: 7273

#Unit 5. Developmental Biology

Hox9 and Hox10 paralogues specify the stylopod, Hox11 paralogues specify the zeugopod, and Hox12 and Hox13 paralogues specify the autopod. This scenario has been confirmed by numerous experiments.

Which of the following experiment correctly describe this scenario?

#Question id: 7272

#Unit 5. Developmental Biology

Few statements regarding the role of disheveled (dsh) and beta-catenin in the development of sea urchin.

A. beta-catenin accumulates predominantly in the macromeres and somewhat in veg2 tier cells.

B. At the fourth cleavage disheveled and β-catenin, both of which are found in the cytoplasm and are inherited by the micromeres.

C. Treating sea urchin embryos with lithium chloride allows β-catenin to accumulate in every cell and transforms presumptive ectoderm into endoderm.

D. When β-catenin is prevented from entering the nuclei (i.e., it remains in the cytoplasm), the vegetal cell fates are specified, and the entire embryo develops as a ciliated ectodermal ball.

Which one of the following options represents a combination of correct statement?

#Question id: 7271

#Unit 5. Developmental Biology

In drosophila, Head formation required higher Bicoid concentrations than thorax formation, because