What did doodle in the narrator dream about the future?

What component of earth’s atmosphere exists entirely as a result of photosynthesis?

At the negative terminal of the battery the electron has electric potential energy. what happens to this energy as the electron jumps from the negative to the positive terminal?

Ahot-air balloon takes off from the ground traveling vertically with a constant upward acceleration of magnitude g/4. after time interval δt, a crew member releases a ballast sandbag from the basket attached to the balloon. how many seconds does it take the sandbag to reach the ground? (express your answer in terms of δt)