Radioactive element ‘C’ decays over time to element ‘D’. Element C has a half-life span of 4 years. If you started with 16 grams of C how many grams of element C would you have after 12 years? 1) 0 grams

2) 1 gram

3) 2 grams

4) 4 grams

5) 6 grams

6) 8 grams

7) 10 grams

8) 12 grams

9) 16 grams

10) 18 grams

Which of the following observation darwin shape his concept of descent with modification? a) species diversity declines farther from the equator. b) fewer species live on islands than on the nearest continents. c) birds live on islands located farther from the mainland than the bird's maximum nonstop flight distance. d) south american temperate plants are more similar to the tropical plants of south america than to the temperate plants of europe. e) earthquakes reshape life by causing mass extinctions.