Which statements about β turns are correct? their purpose is to reverse the direction of the polypeptide chain. there are two types, i and ii, which differ mainly in the conformation about the i+1 and i+2 residue amide bond. they typically contain large, hydrophobic residues. their conformation is held in place through h bonds.

Check the correct box to describe the periodic trends in electronegativity. electronegativity across a period: decreases. increases. electronegativity down a group: decreases. increases.

Identify the electromagnets with poles that are reversed from the electromagnet shown above

Americium-241 undergoes fission to produce three neutrons per fission event. if a neutron-absorbing material is mixed in with this sample so that the rate of neutron production drops down to 1.8 neutrons per fission event, which will be effective at achieving a critical mass? check all that apply. remove a deflective shield surrounding the sample. remove absorbent material mixed in with the sample. compress the sample of americium-241.