All animals with eyes or eyespots that have been studied so far share a gene in common. when mutated, the gene pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. the sequence of pax-6 in humans and mice is identical. there are so few sequence differences with fruit fly pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than five hundred million years ago.
fruit-fly eyes are of the compound type, which is structurally very different from the camera-type eyes of mammals. even the camera-type eyes of molluscs, such as octopi, are structurally quite different from those of mammals. yet, fruit flies, octopi, and mammals possess very similar versions of pax-6. the fact that the same gene produce very different types of eyes is most likely due to
(1) the few differences in nucleotide sequence among the pax-6 genes of these organisms
(2) differences in the control of pax-6 expression among these organisms
(3) the independent evolution of this gene at many different times during animal evolution
(4) variations in the number of pax-6 genes among these organisms

How many copies of each chromosomes should be present in each of the 4 final haploid versions of gamete?

Me plz he did not infringe upon the policy making powers that he felt the constitution gave congress. but the determination of foreign policy became preponderantly a presidential concern. when the french revolution led to a major war between france and england, washington refused to accept entirely the recommendations of either his secretary of state thomas jefferson, who was pro-french, or his secretary of the treasury alexander hamilton, who was pro-british. rather, he insisted upon a neutral course until the united states could grow stronger. which provides the best objective summary of this excerpt? president washington made a good choice when he decided not to accept the recommendations of his advisors and instead insisted that the united states stay neutral during the war between france and england as president, washington believed that the united states should remain neutral in foreign policy even though he had advisors who recommended that he take sides during the war between france and england. washington did not make policy decisions during his presidency because he did not want to interfere with the policy-making powers that the constitution gave congress. washington refused to accept entirely the recommendations of either his secretary of state thomas jefferson, who was pro-french, or his secretary of the treasury alexander hamilton, who was pro-britis

The picture represents a structure of the respiratory system. which is the function of this structure? to bring air into the body to exchange oxygen with carbon dioxide to carry air to the lungs to release oxygen from the body