Researchers in the Netherlands studied the effects of parental care giving in European kestrels over 5 years. The researchers transferred chicks among nests to produce reduced broods (three or four chicks), normal broods (five or six), and enlarged broods (seven or eight). They then measured the percentage of male and female parent birds that survived the following winter. (Both males and females provide care for chicks.) Which of the following is a conclusion that can be drawn from this graph?

#Question id: 2905

#Unit 2. Cellular Organization

With respect to X-chromosome inactivation, which, if any, of the following statements are not correct? 

I. X-chromosome inactivation in mammals begins in the pre-implantation embryo 

II. In humans all diploid cells that carry two normal X-chromosomes are subject to a random pattern of X-inactivation. 

III. Once a decision has been made to inactivate an X chromosome (either the paternal or maternal X), all descendant cells show the same pattern of X-inactivation. 

IV. The inactivated X chromosome becomes a highly condensed Barr body in which genes are silenced across the length of the chromosome.

#Question id: 5044

#Unit 5. Developmental Biology

The cell might not look different from its nearest or most distant neighbors in the embryo and show no visible signs of differentiation, but its developmental fate has become restricted, the process known as-

#Question id: 28443

#Unit 5. Developmental Biology

Vulva is derived from which of the following germ cells?

#Question id: 8906

#Unit 9. Diversity of Life Forms

#Question id: 3252

#Unit 11. Evolution and Behavior

 The unaffected brother of a cystic fibrosis affected girl is referred for genetic counseling. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?  (Cystic fibrosis is an autosomes recessive inheritance with an incidence of 1 in 2500).