Explain why some fibres are called synthetic

You may expect bonds between two atoms which each have n covalent lonic metallic hydrogen

Which real-world scenarios below represent physical and chemical changes? -running a car -exploding fireworks -mixing water and powdered drink mix -combining oil and vinegar to make salad dressing -taking aspirin for a headache -diluting bleach with water-digesting dinner-spreading peanut butter on bread

May someone me with these science questions