Need ! : the color pattern is species of duck is determined by a single pair of genes with three alleles. the d(h) and d(r) alleles are codominant, while d allele is recessive to both. how many phenotypes are possible in a group of ducks that contain all of the possible combinations of alleles?

In an inheritance pattern of codominance, we can see many phenotypes. We should begin by listing all the possible genotypes and associated genotypes: 
Genotypes                  Phenotypes
D(H) D(H)                      H
D(H) D(R)                      HR
D(H) d                            H
D(R) D(R)                      R
D(R) d                            R
d d                                  d

If we look at the phenotypes, there are two ways to get the "H" phenotype, two ways to make the "R" phenotype, one way to make the "HR" phenotype. and one way to make the "d" phenotype. That means there are four separate phenotypes possible. 

To kill bacteria from our body especially from stomach

Answer:

it provides an alternative energy pathway for the reaction to proceed.

explanation:

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.