What is half-life?
a. half-life is a term that describes the time it takes for half of a particle to disintegrate
c. half-life is a term that describes the time it takes for the amount of radioactivity to increase by one half.
b. half-life is a term that describes the time it takes for the amount of radioactivity to go down by one half.
d. none of the above

Apositive rod is placed to the left of sphere a, and the spheres are separated. which best describes the spheres? sphere a is negative and sphere b is positive because protons from sphere a are attracted to the rod and move to sphere b. sphere a is negative and sphere b is positive because electrons from sphere b are attracted to the rod and move to sphere a. sphere a is positive and sphere b is negative because electrons from the rod move to sphere b and protons then move to sphere a. sphere a is positive and sphere b is negative because protons move from sphere b to the rod and also to sphere a.

The velocity of car is 80.0 miles per hour. what is the velocity of car in meters per second? (1 km -0.621 miles) m/s

Describe different biomes. what are some adaptations that organisms (plants or animals) must have to live in each biome?