Polytene chromosomes in salivary glands of Drosophila are formed as a result of

What is the number of chromosomes in human cells during the following phases: Metaphase,Metaphase-$I$,and Metaphase-$II$,respectively?

Arrange the following events of mitosis in correct order and select the correct option from options given below :
$a.$ Movements of chromosome towards opposite pole
$b.$ Movement of centriole towards opposite poles
$c.$ Chromosome align on equator
$d.$ Reformation of nuclear membrane and nucleolus

Which type of cell division occurs in the gonads?

Which of the following processes is necessary for growth?

Chromosomes become short,dense,and distinct,each chromosome consists of a centromere and two chromatids,and the nucleolus and nuclear envelope disappear. During which phase are these changes observed?