The graph below shows the radioactive decay of an isotope of uranium. Bar graph showing time in millions of years on x axis and number of uranium atoms present on y axis. Height of bar corresponding to time 0 million years is 100; time 4500 million years is 50; time 9000 million years is 25; time 13,500 million years is 12.5; and time 18,000 million years is 6.25.

Based on the graph, what is the half-life of uranium?

Consider this plant cell which organelle is labeled g

Which mechanism of transport takes place when solute particles move from a region of high concentration to a region of low concentration? active diffusion isotonic osmosis

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.