The enzyme telomerase extends linear chromosomes by adding nucleotides.

Identify true statements regarding telomerase.

Telomerase has reverse transcriptase activity.

In humans, telomerase adds the six$-$nucleotide sequence $5^{\text{'}}-$ ATACTC $-3^{\text{'}}.$

After the DNA strand is lengthened, telomerase serves as a template for the synthesis of the complementary DNA strand.

Telomerase contains an RNA component that serves as a template for a DNA sequence.

Telomerase extends a DNA strand by adding a repeating sequence of six nucleotides to the $5^{\text{'}}$ end.

The illustration shows four petri plates used for the Ames test. A piece of filter paper, represented by the white circle in the center of each plate, was soaked in one of four preparations and then placed on a petri plate. The four preparations contained

A$.$ purified water as a control;

B$.$ a known mutagen;

C$.$ a chemical whose mutagenicity is under investigation; and

D$.$ the same chemical after treatment with liver homogenate.

The number of revertants, visible as colonies on the petri plates, was determined in each case.