Class 10 Science Chapter 9 MCQ

British scientist J.B.S. Haldane suggested in 1929 that life must have developed from the simple inorganic molecules (such as methane, ammonia, hydrogen Sulphide etc.) which were present on the earth soon after it was formed. He said that the condition on earth at that time could have converted simple inorganic molecules into complex or organic molecules which were necessary for life. The theory of origin of life on earth proposed by Haldane was confirmed by experiments conducted by Stanley L. Miller and Harold C. in 1953.

Here, all the statements are correct. Hence, your answer will be option [D].

The acquired traits of organisms cannot be passed on to their future generations. If we breed some mice, all the progeny of mice will have tails, just like their parents. Now, if we cut the tails of these first-generation mice surgical and breed them, we will get new mice, all with full details. It has been observed that even after cutting the tails of mice for a number of generations, a tail-less mouse is never born. Actually, the cut tail of mice is an acquired trait which is never passed on to their progeny. This is because cutting the tails of mice does not change the genes of their reproductive cells or gametes.

Accumulation of variation over several generation forms new species. Genetic drift accumulates different changes in sub-populations of a species. Also, natural selection may also operate differently in the different geographic location. Eventually different groups of new species will be formed.

Radish and carrot represent homologous structures as they have the same structure or basic design through they are different species.

New species may be formed if the DNA changes are severe enough, such as a change in the number of chromosomes. This leads to new variations.

The maleness of a child is determined by the Y-chromosome in zygote inherited from the father. If X-chromosome is inherited from the father, the zygote will develop into girl.

The incorrect statement is [D] as fat molecules are not related to genes. On the other hand, genes contain information for making proteins in a cell. The proteins synthesized may be enzymes that catalyses biochemical reaction. The enzymes also control the process of making hormones. This explains why A, B and C are correct.

Mendel ensured that he used pure breeding plants for his experiments by letting each variety self-pollinate for several generations

Here, all the statements are correct. Hence, your answer will be option [D]. tors that live on this earth long, long ago.