Because information in the fossil record is incomplete scientists are left with certain biases concerning fossil preservation. explain to of these biases.

the answer is a or when it says crossing over

liquid crystals are matters in a state which have properties between those of conventional liquids and those of solid crystals[1]. liquid crystal is partially ordered and anisotropic. in terms of molecular order, liquid crystal molecules have one-dimensional or two-dimensional long - range order.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds