The mechanisms that contribute to the genetic variation arising from sexual reproduction include:

I:	Independent assortment of chromosomes
II:	Crossing over
III:	Random fertilization

 

1.	I and II only	2.	I and III only
3.	II and III only	4.	I, II and III

Identify the stage of meiotic cell division shown in the given diagram:

The beginning of diplotene is recognized by:

Meiosis results in
1. Production of gametes
2. Reduction in the number of chromosomes
3. Introduction of variation
4. All of the above 

Meiosis occurs in organism during
1. Sexual reproduction 
2. Vegetative reproduction
3. Both sexual and vegetative reproduction
4. None of these above

During anaphase I of meiosis
1. Homologous chromosomes separate 
2. Non-homologous autosomes separate
3. Sister chromatids separate
4. Non-sister chromatids separate

Meiosis is characterised by
1. Reduction division 
2. Equal division
3. Both reduction and equal division
4. None of these

A bivalent of meiosis- I consists of
1. Two chromatids and one centromere
2. Two chromatids and two centromeres
3. Four chromatids and two centromeres
4. Four chromatids and four centromeres

Cells which are not dividing are likely to be at

Which of the events listed below is not observed during mitosis?
1. Chromatin condensation
2. Movement of centrioles to opposite poles
3. Appearance of chromosomes with two chromattids joined together at the centromere
4. Crossing over