$69.$ The primary application of $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$ in the petrochemical industry is the production of various polymers and resins used in construction, automotive, and packaging industries, while $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$ is primarily used as a solvent and intermediate in the manufacturing of pharmaceuticals and agrochemicals. $($a$)$ Polyethylene, methanol $($b$)$ Polypropylene, acetone $($c$)$ Butadiene, acetylene $($d$)$ Ethylene, ethanol

$70.\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$ and $\_\_\_\_\_\_\_\_\_\_\_\_\_$ are common intermediates in the production of synthetic rubbers, plastics, and pharmaceuticals in the petrochemical industry, while $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$ is used as a precursor for various chemicals such as methanol and ammonia. $($a$)$ Butadiene, styrene, synthesis gas $($b$)$ Acetylene, butylene, ethylene $($c$)$ Ethanol, methanol, hydrogen $($d$)$ Hydrogen, propylene, butylene