Can y’all please help me with this I would greatly appreciate it

Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b.slope c.benchmark d. index contour

In which block of the periodic table is uranium (u) found? s blockd blockp blockf block

Which is a characteristic of the electron sea model for metallic bonding? molecular orbitals overlap to produce bands. electrons flow easily between metal nuclei. electrons are in fixed positions in the orbitals. atomic nuclei are arranged in an irregular pattern.