The la brea tar pits in los angeles are the site of millions of fossils from the ice age. woolly mammoths, giant sloths, dragonflies, and other plants and animals from this era have been found in these pits. scientists at the tar pits discovered that many of the smaller animals they extracted from the pits still exist around los angeles today. but many of the larger mammals—such as woolly mammoths and saber-toothed tigers—are now extinct. why do you think this is the case? what can scientists learn about los angeles’ climate history by studying the specimens found in these tar pits?

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.

Chloroplasts and bacteria are in size. a. similar b. at different ends of the size range c. exactly the same d. none of these

We can be sure that a mole of table sugar and a mole of vitamin c are equal in their 1) mass in daltons. 2) mass in grams. 3) number of molecules. 4) number of atoms. 5) volume.