Why do plants not have a exsited before cyanobacteria started producing oxygen?

Which of the following describes a referee's job? A. Cheering the players on. O B. Keeping score for the team on offense. C. Supervising the game to make sure teams are playing fairly. O D. Settling arguments between players.

the wires inside a cable each have there own plastic insulation. why does the insulasion have diffrent colours

Carmen simplifies the expression (4y+8x+6) + 25 + (4x+6y+7). The coefficient of the variable y in her simplified answer is

There are 8 elements that together make up 98.5% of earth crust oxygen 46.6% aluminum 8.1% iron 5.0% calcium 3.6% sodium 2.8% potassium 2.6% magnesium 2.1% and silicon what percentage of earth crust is silicon

A particle leaves the origin with an initial velocity v → = (3.00iˆ) m/s and a constant acceleration a → = (-1.00iˆ - 0.500jˆ) m/s2. When it reaches its maximum x coordinate, what are its (a) velocity and (b) position vector?

The forklift exerts a 300.0 N force on the box and moves it 15.0 m into the air. How much work does the forklift do? A. 500 J B. 1.50 * 10^3 J C. 4.50 * 10^3 J D. 0.00 J

Why the room gets hot even we open the door of refrigerator?

What effect will taking a dose of antibiotics that is too small have on the bacteria you are trying to destroy? a. all of the bacteria will pass on their genes b. none of the bacteria will pass on their genes c.

Multiply 0.00032 cm by 4.02 cm and express the answer in scientific notation

Apply why does a box on the seat of a car slide around on the seat when the car speeds up slows down or turns a corner?