Help me plz .

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

Omg imgonnafailnfiedkla use complete sentences to explain how the mass of hydrogen is conserved during cellular respiration.

How did planetesmals form planets? a. they broke apart into smaller chunks.b. they collided and stuck together.c. they cooled and pulled ice together.d. they began to rotate.