Question

in the 1970s, what element was removed as an additive from gasoline?
palladium
zinc
lead
copper

Explanation:

In the 1970s, lead was removed as an additive from gasoline due to its harmful environmental and health effects. Lead - based additives like tetra - ethyl lead were used to prevent engine knocking. However, lead is a toxic heavy metal. Its release into the environment through vehicle exhaust led to widespread contamination of air, soil, and water. This had significant negative impacts on human health (especially on the nervous system, especially in children) and the ecosystem. Palladium is used in catalytic converters (not as a gasoline additive in the context of being removed in the 1970s). Zinc and copper are not typically associated with being removed as gasoline additives in the 1970s in the same way as lead.

Answer:

lead