Dr. smith's parents have normal hearing. however, dr. smith has an inherited form of deafness. deafness is a recessive trait that is associated with the abnormal allele d. the normal allele at this locus, associated with normal hearing, is d. dr. smith's parents could have which of the following genotypes? a) dd and ddb) dd and ddc) dd and ddd) dd and dd

The correct option is C) Dd and Dd

Explanation:

To explain the answer, lets make a punnet square with a cross between Dd and Dd.

       D       d

D     DD    Dd

d      Dd     dd

As deafness is a recessive trait, this means that both the alleles in a person should be same and recessive for that trait to occur in the phenotype. A cross between heterozygous carriers show that there will be a 25% probability that the offsprings produced will get the recessive alleles and hence they will be deaf. 50% of the offsprings will have the chance to be carriers like their parents. And there willbe a 25% chance that they will have normal homozygous alleles.

answer:

the water molecules are transferred from the roots to the stem or top parts of the tall tree because of important properties of water which are adhesion, cohesion and capillary action. cohesion is the property of water molecules keeps water molecules in a combined state by sharing of bonds between them at the atomic level. adhesion allows the interaction of water molecules with other substances or substrate. adhesion will cause the attachment of water molecules to the wall of the vessel (xylem) of the plant. capillary action occurs when the adhesive force to the vessel wall is stronger than the cohesive force between water molecules. capillary action mimics the transfer of water from a tube or pipe. in this way water utilizes its property to transfer water from down to top level of the plant.  

the answer is b. glad to .