Mammals did not descend directly from dinosaurs, but mammals embryos have placodes. Use the info about scales and feathers to explain why mammal embryos and dinosaur embyros each have placodes.

What is a coast of using technology to transport water? a. cities can be built in otherwise uninhabitable areas. b. crops can be irrigated and grown in new areas. c. floods can be averted in flood-prone areas. d. freshwater supplies can be depleted in an area.

Question 4 using myplate's daily food plant for 2000 kilocalories as a reference, the servings from the protein foods group in this menu are a. adequate overall, and consistent with the dietary guidelines 2010 recommendations. b. short 2 ounce equivalents. c. inadequate in terms of the recommendations for a 2000 kcal diet. d. adequate overall, but inconsistent with the dietary guidelines 2010 recommendations.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.