Which refers to the light-sensitive surface at the back of the eye? 1.lens
2.iris
3.retina
4.optic nerve

Why reason best illustrates why hershey and chase chose to use viruses in their experiment?

You and a group of friends are spending your vacation hiking through the mountains. it is cold in the mountains. you will be expending a lot of energy while hiking and you will need plenty of energy to keep you warm. you should pack foods high in to provide the most energy or kilocalories per gram of food. a) carbohydrates b) lipids (fats) c) proteins d) sugars

How does the closing of the ductus arteriosus and ductus venosus alter circulation in an infant? a. increases blood flow to the pulmonary artery and increases blood flow to the umbilical vein b. increases blood flow to the pulmonary artery and reduces blood flow to the umbilical vein c. reduces blood flow to the pulmonary vein and increases blood flow to the umbilical artery d. reduces blood flow to the pulmonary vein and reduces blood flow to the umbilical artery