Science M.C.Q

(C) Growth hormones under the influence of the enzymes coded by a gene.

The two versions of a trait, which are brought in by the female and male gametes are situated on the copies of the same chromosome.

According to law of dominance, a trait is represented by two contrasting factors of a gene in a heterozygous individual; the allele/ factor that can express itself in heterozygous individual is called as dominant trait. The other factor whose effect is masked by presence of dominant factor, is called recessive factor.

Environmentally determined traits are acquired. Size of body depends on nutritional status, health conditions etc.

Homologous organs perform different functions and have different appearance but share common basic structural plan and origin. Analogous organs perform similar function and have similar appearance but have different basic structure and origin.

Scientists believe that all life originated in sea water.

Mendel proposed some Laws of Inheritance.They are three in number.
Law of Dominance
Law of Segregation
Law of independent assortment.

Evolution is the sequence of gradual changes, which take place in primitive organisms over millions of years, due to which new species are formed.

In progeny, all plants obtained will be tall because tallness is the dominant trait, while dwarfism is the recessive trait.

Homologous organs are defined as the organs which have same structure but different functions. Radish and carrot is a pair of homologues organs as they are modified roots.

Hormone and enzymes are made up of proteins and formation of any particular protein is also controlled by a particular gene. But fat formation does not depends on gene. Hence, all other options are correct.

Analogous organs are that which are different in origin but similar in function.

Gregor Mendel is the father of genetics. When he explained about heredity for the first time ever, the term "Gene" which is now being used, was not given.
According to his explanations, he called them 'Factors' which are otherwise known as Genes.

Mendel used pea plants for his experiments on heredity.

The term ‘cross’ in the question indicate towards cross fertilization.

Fats are not synthesised by genes present on chromosomes.

Spinach has not been produced from wild cabbage by the process of artificial selection.

The organs which perform a similar function, but have different basic structures are called analogous organs.
For example : wings of insects and birds are analogous.

Mendelism is related to heredity.
The prominent law given by Mendel proved its relationship with inheritance.
The law of segregation states that each character is regulated by a gene which exists in two forms for a particular character known as allele which segregates into different gametes.
The law of independent assortment states that alleles for separate traits are passed independently of one another from parents to offspring.

Analogous organs are those which do not share a common ancestor but perform common function. Wings of insects and bats both perform the same function of flight but are not common in origin. Hence, wings of insects and wings of bats are analogous organs in animals.
Hence, Potato and sweet potato have different origin but similar function so are analogous organs in plants.

Analogous organs are organs that have a different origin but have the same functions.
In birds, the wings are modified forelimbs, while in insects they are made of the cuticle.
But the wings of a housefly and the wings of a pigeon have the same function of flying.

They have similar design and origin.

Oxygen was absent in early earth atmosphere.

Darwin believed that certain variations are better adapted to environmental conditions.
These adaptations got accumulated over a period of time in each generation, and ultimately gave rise to new species.
Thus, time was the most important requirement in speciation.
Further evolution is a continuous process in the sense that intermediate forms between ancestors and present-day modern species did exist in past but later on got extinct.

Acquired characters are characteristics that are gained by an organism after birth as a result of external influences or its own activities, that change its structure or function.
These characters cannot be inherited.
For example, If we breed a group of mice whose tails are removed by surgery, then these tailless mice will not have tailless progeny because removal of the tail cannot change the genes of the germ cells of the mice.

A genotype is the genetic makeup/constitution of a cell of an organism.
A phenotype is an external appearance caused by the presence of a particular genotype.
A trait indicates the specific characteristic of an individual.
An allele is a variant form of a gene.