What is the correct sequence of the following events
$1.$Formation of the chromosome theory of heredity
$2.$Experiments which proved that $DNA$ is the hereditary material
$3.$Mendel's laws of inheritance-discovery
Code :
$1, 3$ and $2$
$1, 2$ and $3$
$3, 1$ and $2$
$2, 1$ and $3$
Match the terms in column $I$ with their description in column $II$ and choose the correct option.
Column $-I$ | Column $-II$ |
$(A)$ Dominance | $(i)$ Many genesgovern a single character |
$(B)$ Codominance | $(ii)$ In a heterozygousorganism only one allele expresses itself |
$(C)$ Pleiotropy | $(iii)$ In a heterozygousorganism both alleles express themselves fully |
$(D)$ Polygenic | $(iv)$ A single gene inheritanceinfluences many characters |
Match the Column - $I$ with $II$
Column - $I$ | Column - $II$ |
$(a)$ Pleiotropic gene | $(i)$ Both allele express equally |
$(b)$ Co-dominance | $(ii)$ Change in nucleotide |
$(c)$ Epistasis | $(iii)$ One gene shows multiple phenotypic expression |
$(d)$ Mutation | $(iv)$ Rust disease |
Match the following columns.
Column $- I$ | Column $- II$ |
$(w)$ Blood group | $(a)$ Polygenic inheritance |
$(x)$ Skin colour | $(b)$ Aneuploidy |
$(y)$ Mendelian disorder | $(c)$ Incomplete dominance |
$(z)$ Chromosomal disorder | $(d)$ Sickle-cell anaemia |
$(e)$ Co-dominance |
Pick out the correct statements.
$(1)$ Haemophilia is a sexlinked recessive disease.
$(2)$ Down’s syndrome is due to aneuploidy.
$(3)$ Phenylketonuria is an autosomal recessive gene disorder.
$(4)$ Sickle cell anaemia is an $X$-linked recessive gene disorder.
A man can inherit his $X-$chromosome from his