Which feature of cycads distinguishes them from most other gymnosperms? 

1. They have exposed ovules

2. They have flagellated sperm

3. They are pollinated by animals

#Question id: 5140

#Unit 5. Developmental Biology

Following statements regarding to the Ectodermal competence and the ability to respond to the optic vesicle inducer in Xenopus.

A. The optic vesicle is able to induce lens formation in the posterior portion of the ectoderm but not in the anterior portion.

B. If the optic vesicle is removed, the surface ectoderm forms either an abnormal lens or no lens at all.

C. Only head ectoderm is competent to respond to the signals from the optic vesicle by producing a lens.

D. The head ectoderm appears to secrete two paracrine factors BMP 4 and FGF8, which involves in the activation of lens-specific genes such as crystallin.

Which of the following combination is incorrect?

#Question id: 6950

#Unit 5. Developmental Biology

In mammalian development, the embryo will form from which population of cells?

#Question id: 4345

#Unit 3. Fundamental Processes

For a repressible operon to be transcribed, which of the following conditions must occur?

#Question id: 13030

#Unit 13. Methods in Biology

#Question id: 297

#Unit 1. Molecules and their Interaction Relevant to Biology

The boiling point of water is exceptionally high because