Question

Basic set of chromosome number is called
(a) Euploid
(b) Polyploid
(c) Aneuploid
(d) Monoploid

Answer 1

An individual that contains one half the normal number of chromosomes. These alleles generally are not a problem in diploids because their effects are masked by dominant alleles in the genome. It is very rare in nature because recessive lethal mutations become unmasked, and thus they die before they are detected.

Complete answer:
The basic set of chromosome numbers is called monoploid. Fundamental chromosome number, x (additionally called monoploid number): the number of various chromosomes that make up a single complete set. (In a diploid organism with 10 sets of chromosomes, x = 10)

Additional Information: Ploidy: number of essential chromosome sets (a diploid has 2 sets; a hexaploid has 6 sets).
Euploid: An organism containing multiple of the basic chromosome set. Most euploid species are diploids. There are a couple of instances of monoploidy. For instance, in certain types of honey bees, wasps, and ants, the females are diploid and males are monoploid. The male grows parthenogenetically from unfertilized eggs, in this way gets a haploid arrangement of chromosomes from their mother. Male can create gametes utilizing modified mitosis.
Monoploid: An organism with one chromosome set (in basically diploid taxa). Monoploids can likewise be made artificially in certain species. For instance, geneticists create haploid embryo because genotype in haploids is revealed by phenotype
Polyploid: An organism containing more than two chromosome sets
Haploid number, n: number of chromosomes in the gametes (In diploid organism n=x, yet this isn't valid for polyploid species. Wheat is a hexaploid with 42 chromosomes; for this situation x=7 and n=21.)
Allopolyploids: The polyploids made by hybridization between various species (homeologous chromosomes)
Autopolyploids: The polyploids made by chromosome duplication inside within species

So, the correct answer is ‘monoploid’.

Note: Some plant polyploids reproduce asexually because they are sterile. This is because of irregular segregation during meiosis, prompting aneuploid gametes. Triploidy is quite often sterile (bananas are proliferated by cuttings, some apple species by grafts, and different species by bulbs).