Answer:
9:3:3:1
Explanation:
If two parents for a dihybrid cross are fully heterozygous for two genes, the phenotype ratio comes 9:3:3:1. Here, the alleles of both genes should exhibit complete dominance-recessiveness. This means that one allele of a gene should be able to mask the expression of its another allele. Similarly, alleles of one gene genes should assort in a random manner during anaphase-I irrespective of the assortment of alleles of another gene.
Under these conditions, each parent produces four types of gametes in equal proportion. And the random fusion of these gametes gives progeny in 9:3:3:1 phenotype ratio.
For example, a dihybrid cross between TtRr and TtRr would produce progeny in the following phenotype ratio=
9 tall and red: 3 tall and white: 3 dwarf and red: 1 dwarf and white
Here the allele T gives "tallness" while the allele "t" gives "dwarfism". The dominant allele "R" gives "red flowers" while the recessive allele "r" gives white flowers.
Warm air rises cool air stays closer to earth
<span>Lysosomes contain digestive enzymes.
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Mitochondria, nucleus, chromosomes, ribosomes
To easy remember it,
Phloem, has the (f) sound, so it carries food and nutrition like sugars all around the plant, up and down movwment.
while Xylem carries water and minerals, from down the soil up to the plant, only up movement.
