Can someone pls help me with this pls

What semimetal can form four single covalent bonds.

Needthe meter is the standard unit for: 1) height 2) length 3) weight 4) mass

Which of the following contributes to the structural rigidity of cellulose? adjacent glucose polymers are stabilized by hydrogen bonding. glucose residues are joined by (α1→4) linkages. cellulose is a highly branched molecule. the conformation of the glucose polymer is a coiled structure.