3. draw the two stereoisomers of 1,3-dibromocyclobutane refer to the structure below to answer the following questions:
4. which of the labeled bonds in the structure are equatorial bonds?
5. which of the labeled bonds are trans to bond b?
6. which labeled bonds have a 1,3-diaxial interaction with each other?

Which supports the idea that birds and butterflies both have wings but they do not have a common ancestor with wings? a. the wings are analogous structures that evolved differently and do not have a similar internal structure. b. the wings are homologous structures that evolved differently and do not have a similar internal structure. c. wings of birds are vestigial structures, but the wing structures of bats are not vestigial. d. wings of bats are vestigial structures, but the wing structures of birds are not vestigial

Three alkali metals in group 1 are a. calcium, strontium, barium b. boron, aluminum, gallium c. sodium, potassium, rubidium d. fluorine, iodine, chlorine

How does the principle of electromagnetism explain the interaction between earth’s magnetic field and the solar wind?