Doorknobs and other surfaces in clinical settings are often coated with or to prevent the transmission of microbes.

The correct answer would be copper, nickel, or zinc.

Explanation:

Heavy metals such as copper, zinc, nickel have antimicrobial properties due to which they are used in various places to prevent microbial growth. For example, copper sulfate is used in fish tanks and swimming pools to prevent algal growth. Metallic copper and/or copper linings in incubators also help in reducing microbial contamination.  

Coating of nickel or zinc is also used for the same purpose.

Thus, the correct answer would be copper, nickel, or zinc.

No lactose individuals have two biological parents that are lactose intolerant

Explanation:

In this case lactose intolerance would be coded for a recessive gene (r). if both parents are lactose intolerant the would both be the genotype (rr) . For individual to be lactose intolerant atleast one parent most be lactose tolerant posesing the dominant (R) gene. Which both parents in this example lack.