Question

19. Generally, there are two copies of a set of genes in body cell, then how
cells make a single set of genes?
20. What is variable resistance ?​

Answer 1

Answer:

19. There are 22 chromosomes pairs (autosomes) and a pair of sex chromosomes (allosomes). Thus, a single set of genes is formed from the two copies. ... Meiosis, therefore, helps the germ cells make a single set of genes (haploid) from the normal two copies (diploid).

20. Potentiometer

A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.

Answer 2

19) There are 22 chromosomes pairs (autosomes) and a pair of sex chromosomes (allosomes). Thus, a single set of genes is formed from the two copies. ... Meiosis, therefore, helps the germ cells make a single set of genes (haploid) from the normal two copies (diploid).

20) A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.