Which of these evolutionary agents is most consistent at causing populations to become better suited to their environments over the course of generations?

#Question id: 10881

#Unit 10. Ecological Principles

In deep water, which of the following abiotic factors would most limit primary productivity?

#Question id: 22016

#Unit 1. Molecules and their Interaction Relevant to Biology

#Question id: 15678

#Unit 2. Cellular Organization

#Question id: 7219

#Unit 5. Developmental Biology

Following statements are regarding to the role of the Disheveled and β-catenin proteins in specifying the cells of the sea urchin embryo.

A. During normal development, β-catenin accumulates predominantly in the micromeres and somewhat less in the veg2 tier cells.

B. In embryos treated with lithium chloride, β-catenin accumulates in the nuclei of all blastula cells and the cells of the animal pole become specified as ectoderm.

C. When β-catenin is prevented from entering the nuclei (i.e., it remains in the cytoplasm), the vegetal cell fates are not specified, and the entire embryo develops as a ciliated ectodermal ball.

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 specified as endoderm and mesoderm .

Which of the following statements are true?

#Question id: 10498

#Unit 6. System Physiology – Plant

Which one of the following inhibitor that inhibits blue light–stimulated stomatal opening and the inhibition is concentration dependent, while does not block red light–stimulated opening.