The electrons in the outermost shell of the covalent compounds are shared by nearby atoms. As there are no free electrons for conducting electricity, the covalent compounds are perfect insulators at absolute zero. As the temperature increases, some electrons move from valence band to conduction band. This gives rise to conductivity. But as the numbers of charge carriers are very low, covalent compounds are poor conductors. On the other hand metals are good conductors cause of their bonding. Metallic bonding consists of a sea of electrons rather than discreet bonds. The free electrons are able to move freely. Since electricity and heat need electrons to move, the bonding promotes conductivity.
Answer: The genotype ratio of offsprings of a cross between one homozygous tall plant and one heterozygous tall plant is 2TT:2Tt
The phenotype ratio is that all offsprings will be tall.
The genotype ratio of a cross between two heterozygous red flowers is 1RR:2Rr:2rr. The phenotype ratio is 3 Red flowers: 1 white flower.
Explanation: From the information given, tall is dominant and short is recessive while red is dominant and white is recessive.
Let T represent the allele for tall height, t represent the allele for short height, R represent allele for red flowers and r represent allele for white flowers.
The genotype of a homozygous tall plant is TT, the genotype of a heterozygous tall plant is Tt, the genotype of a heterozygous red flowered plant is Rr.
The possible genotypes of offsprings of a cross between one homozygous tall plant and one heterozygous tall plant are TT and Tt.
Tt will manifest outwardly as tall because T is dominant over t. Therefore, all the offsprings will be tall.
The possible genotypes of a cross between two heterozygous red flowers are RR, Rr and rr. RR will manifest as red, Rr will also manifest as red because R is dominant to r while rr will manifest as white because white allele (r) is recessive. Therefore 3 plants will be red-flowered while 1 plant will be white flowered.
See the attached punnet squares for details of the cross.