Mutant Saccharomyces cerevisiae cells that lack the gene encoding securin can divide more or less normally by mitosis, without significant chromosome segregation defects. Cells harboring a nondegradable version of securin, on the other hand, arrest in metaphase as expected, since they cannot activate separase to enter anaphase. Similarly, cells lacking Cdc20 (an APC/C activator) arrest in metaphase, since they cannot activate APC/C. Finally, cells lacking both securin and Cdc20 arrest in anaphase: they manage to separate sister chromatids, but do not progress much further. These results suggest that in wild-type cells:. A. Degradation of securin is necessary to trigger sister-chromatid separation. B. Degradation of securin is sufficient to trigger sister-chromatid separation. C. Cdc20–APC/C is NOT necessary for sister-chromatid separation. D. Cdc20–APC/C is NOT necessary for later events in anaphase. E. All of the above.

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.

Amouse that is homozygous for the dominant trait has the genotype . it has . a mouse that is homozygous for the recessive trait has the genotype . it has . image of fur color of mice

Why is earth's outer core hotter than earth’s oceanic crust? earth’s oceanic crust is denser than earth’s outer core is. earth’s oceanic crust has lava flowing from the mantle. earth’s outer core has a composition of solid iron and nickel. earth’s outer core is deeper within earth than oceanic crust is.