Various types of damage can lead to acute inflammation, including cuts and abrasions, heat, and microbial damage. Some microbes have structures which can trigger the acute inflammatory response when they invade tissues. What structural characteristics common to Gram-negative bacteria may trigger the acute inflammatory response

Gram negative bacteria don't retain purple color as they contain thin cell wall which is composed of peptidoglycans present between inner cytoplasmic cell membrane and bacterial outer membrane.

Explanation:

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The outer membrane is important as it protects them from antibiotics,detergents that damages the peptidoglycans of cell membrane.The outer membrane is composed of lipopolysaccharide that secrets lipid A component which causes toxic reaction.This toxic reaction creates different health hazards like high fever,increase respiratory rate,low blood pressure etc.Braun's lipoprotein present between outer membrane and peptidoglycans by a covalent bond.

It would be the second choice the phenotype