Helpp! based on the definitions above, identify each of the following as biotic (B) or abiotic (A)

the sand in the desert __

the bacteria in a lake __

pollen from a plant __

pollution from an oil refinery __

What determines the average kinetic energy of the particles in a gas? a. the number of collisions b. the number of particles c. the size of the particles d. the temperature

Iwould appreciate if someone could me.

Asample of hydrated tin (ii) chloride (sncl2) has a mass of 4.90 g. when it is dehydrated, it has a mass of 4.10 g. which is the correct chemical formula for the hydrate? sncl2•2h2o          sncl2•4h2o          sncl2•6h2o