If there are 13 pairs of homologous chromosomes in a cell what is the haploid number?

n = 13

Explanation:

The haploid cell is the one which contains a single set of chromosomes or half (n, haploid) of the normal number of chromosomes in diploid cells (2n, diploid).

If you have 13 pairs of homologous chromosomes, diploid number will be 2n=26

option a is correct i.e.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.

b. heterotroph

explanation: