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

What we see as "moonlight" is really reflected sunlight. True or False?

The top of the cylinder head is sealed by the A. valve cover. B. oil retainer. C. oil pan. D. front cover.

Potassium Permanganate is used for purifying drinking water, because A. it is a sterilising agent B. it dissolves the impurities of water C. it is a reducing agent D. it is an oxidising agent

In this excerpt from "an episode of war" by stephen crane, why does the doctor promise not to amputate the lieutenant's arm?

What is the general aerobic activity recommendation for an exercise frequency that is at least five days per week?

A ball of mass 5.0kg is lifted off the floor a distance of 1.7m. 1. What is the change in the gravitational potential energy of the ball? 2. Now you release the ball from rest, and it falls to the floor.

What is the device to break a circuit called?

A 3 column table with 5 rows labeled table A. The first column is labeled voltage in volts with entries 1.0, 5.0, 10, 20, 50. The second column is labeled current: calculated in amps with no entries.

When you stack three flashlight batteries in the same direction, you get a voltage of 3*1.5 volts = 4.5 volts. What voltage do you get if one of the batteries is turned to face in the opposite direction? a) 0 volts b) 1.5 volts c) 3 volts d) - 4.

If an ant were scaled up to the size of an elephant, the ant would be