If activation energy must be used before a chemical change happens, then what is required before a chemical change? Answer choices: - kinetic energy - energy usage - activation push - activation energy - activation switch - activation power - Burning fuel and air - Evaporation
activation energy

If acar engine converts a fuel of hydrocarbons into motion through combustion, then acar engine uses what to aid in combustion? Answer choices: - carbon dioxide - electricity - organic molecules - thrust - hydrocarbons - a hydraulic system - kinetic energy - fossil fuels
hydrocarbons

Q: If the method used by cells to reproduce is how organisms grow and repair themselves, then the method used by cells to reproduce is how organisms grow and what? Answer choices: - photosynthesis - biological diversity - repair themselves - destroy themselves - organize themselves - It helps them survive - competing for resources - remove themselves
A: repair themselves

Question: If phase changes do not change energy contained in the matter, then what property of matter is not changed during a phase change? Answer choices: - motility - sweating - energy - cold - nucleus - density - apoptosis - an object
Answer: energy

*Question*
If lung cancer can be caused by direct or passive inhalation, then what can be caused by direct or passive inhalation? Answer choices: - skin grafts - prolonged thirst - science - Toxicity - lung cancer - negative - friction - craters
**Answer**
lung cancer

(Q).
If cars harm the respiratory system, then what harms the respiratory system? Answer choices: - coal - oxygen - tar - cigars - breathing - silence - sulfur - cars
(A).
cars