How did oxygen (O2) get into Earth's atmosphere?

you travel at an average speed of 20km/h in a straight line to get to your grandmother's house. it takes you 3 hours to get to her house. how far away is her house from where you started?

the similarities and differences between how both producers and consumer use money.

What do you observe as you immerse the empty jug in a bucket which contains water? Explain why you observe this phenomenon.

A passenger jet in the air increases its speed. does the downward force of air on the top of the wings increase or decrease? does the net lifting force of the air on the wings increase or decrease?

Ampere=Coulomb/Second but our book says ampere is a fundamental/basic unit, is it worng

Describe the factors that form deep currents

A comet is cruising through the solar system at a speed of 50000 kilometers per hour for 4 hours time. What is the total distance traveled by the comet during this time in kilometers, miles, and light years?

A gas in a closed container is heated with 12J of energy, causing the lid of the container to rise 3m with 5N of force. What is the total change in energy?

What are illuminated objects?

During one year a population of blue jays has zero population growth. which must be true about the blue jay population at the end of the year compared to the beginning of the year?