Which of these is most like cast and mold fossils?

Shells, bone, and wood often form as molds or casts. Some trace fossils (ichnofossils), such as tracks and burrows can form as casts or molds. Tracks and burrows can provide clues to the behavior and biomechanics of an organism while it was alive. Concretions often encapsulate a fossil mold and cast.

Explanation:

there ya go mate ^^

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.