If a radiographic substance's half-life is 20 years, how much of a 40 gram sample will be left after 60 years?

A. 5 grams

B. 10 grams

C. 20 grams

D. 30 grams

Which of the following nations does not possess nuclear weapons? a. China b. France c. India d. Spain

Select the best answer for the question. 1. Solve for b in the equation - b + 21 = - 13. O A. b = 9 O B. b = - 9 O C. b = -34 O D. b = 34

What sometimes occurs when reclaimed water is used in agriculture? a. crop death b. overtillage c. pharmaceutical accumulation d. increased land use

Which East Asian country remains poorly developed and isolated under a Communist regime? A. Taiwan B. Japan C. North Korea

The earth is spherical. What occurs when Cartographers attempt to change the sphere into a one dimensional flat map?

Which explains upwelling in the oceans? a. coastal winds blow cold surface water out to sea. deeper, nutrient-rich, warm water flows upward to replace the surface water. b. wind near the coastline blows warm surface water away from the land.

Sedimentary rocks blank. form below the crust

The lands the Netherlands have reclaimed from the sea are known as polders. True False

Where is rice grown and the percentage of production those countries produce

What force acts again capillary action as water moves through the ground