Matthew Meselson and Franklin Stahl demonstrated that DNA replication is semiconservative in bacteria. Choose the correct description of their experiment. A. Meselson and Stahl initially cultured E. coli in medium containing only 15N until all cells contained only 15N/15N DNA. They then cultured the 15N/15N E. coli in normal medium (14N) and collected samples after one, two, and three rounds of DNA replication. B. Meselson and Stahl initially cultured E. coli in medium containing both 14N and 15N until all cells contained only 14N/15N DNA. They then cultured the 14N/15N E. coli in normal medium (14N) and collected samples after one, two, and three rounds of DNA replication. C. Meselson and Stahl initially cultured E. coli in medium containing both 14N and 15N until all cells contained only 14N/15N DNA. They then cultured the 14N/15N E. coli in medium containing only heavy nitrogen (15N) and collected samples after one, two, and three rounds of DNA replication. D. Meselson and Stahl initially cultured E. coli in medium containing only 15N until all cells contained only 15N/15N DNA. They then cultured the 15N/15N E. coli in medium containing both 14N and 15N and collected samples after one, two, and three rounds of DNA replication.

In a hypothetical breed of dogs, coat color is controlled by two genes. there are six different coat colors in this breed: black, brown, cream, gray, silver, and tan. consider the following crosses. cross 1: black females from a lineage of all black dogs are crossed with brown males from a lineage of all brown dogs. f1 males and females are all black. when f1 are intercrossed, f2 males and females are black or brown. cross 2: black females from a lineage of all black dogs are crossed with tan males from a lineage where all males are tan and all females are cream. f1 males are black, f1 females are gray. when f1 are intercrossed, f2 males and females are black, brown, gray, or tan. cross 3: silver females from a lineage where all females are silver and all males are gray are crossed with brown males from a lineage of all brown dogs. f1 males and females are all gray. when f1 are intercrossed, f2 males are black, brown, gray, or tan, f2 females are cream, gray, silver, or tan. select the correct statements regarding the mode of inheritance of the coat color genes. a) both genes are x-linked. b) both genes are autosomal. c) one of the genes modifies the expression of the other gene. d) each gene has an additive effect on the intensity of coat color. e) each gene independently specifies three colors. f) one of the genes is autosomal, and the other is x-linked.

The cluster of developing cells from conception until birth is called an

Ascientist is conducting an investigation that involves water, silver, carbon dioxide, and oxygen gas which group of statements best describes all of the materials he is using in the investigation?