When males produce two different types of gametes (e.g., with or without X, or X and Y), this mechanism of sex determination is called male _______.
The production of two different types of gametes by males (either with or without X, or X and Y) is designated to be the example of male heterogamety.
Question 242 of 519
📘 CLASS XII
The Law of Independent Assortment was proposed by Mendel based on his observations on _______ crosses (crosses between plants differing in two traits).
Mendel proposed the Law of Independent Assortment based upon observations on dihybrid crosses, where the two pairs of traits segregated independently.
Question 243 of 519
📘 CLASS XII
In a dihybrid cross, the F2 generation exhibited a phenotypic ratio of 9 Round, Yellow : 3 Wrinkled, Yellow: 3 Round, Green : 1 Wrinkled, Green, which is a combination series of 3:1 ratio of each trait and is denoted as _______.
In the dihybrid cross, the phenotypes appeared in the ratio 9:3:3:1.
Question 244 of 519
📘 CLASS XII
Mendel published his work on inheritance of characters in _______ but it remained unrecognised till 1900.
Mendel published his work on inheritance of characters in 1865 but it remained unrecognised till 1900.
Question 245 of 519
📘 CLASS XII
Mendel’s approach of using _______ to explain biological phenomena was totally new and unacceptable to many of the biologists of his time.
Mendel’s approach of using mathematics to explain biological phenomena was totally new and unacceptable to many of the biologists of his time.
Question 246 of 519
📘 CLASS XII
In 1900, Mendel's results were independently rediscovered by de Vries, Correns and _______.
In 1900, three Scientists (de Vries, Correns and von Tschermak) independently rediscovered Mendel’s results on the inheritance of characters.
Question 247 of 519
📘 CLASS XII
Due to advancements in microscopy around 1900, scientists were able to carefully observe cell division, leading to the discovery of structures in the nucleus called _______ (colored bodies).
Advancements in microscopy led to the discovery of structures in the nucleus that appeared to double and divide, called chromosomes (colored bodies).
Question 248 of 519
📘 CLASS XII
Walter Sutton and Theodore Boveri noted that the behaviour of chromosomes was _______ to the behaviour of genes and used this parallelism to explain Mendel’s laws.
Walter Sutton and Theodore Boveri noted that the behaviour of chromosomes was parallel to the behaviour of genes.
Question 249 of 519
📘 CLASS XII
The two alleles of a gene pair are located on homologous sites on _______ chromosomes.
The two alleles of a gene pair are located on homologous sites on homologous chromosomes.
Question 250 of 519
📘 CLASS XII
Thomas Hunt Morgan worked with the tiny fruit fly, Drosophila melanogaster, to provide experimental verification of the _______ theory of inheritance.
Experimental verification of the chromosomal theory of inheritance was done by Thomas Hunt Morgan and his colleagues using Drosophila melanogaster.
