Based on radiometric dating and the rock and fossil record, scientists have concluded that life has been present on earth a. for about 1 billion years. b. for about 50,000 years. c. for no more than 10 million years. d. for at least 3.5 billion years.

*will mark brainliest to the first and correct answer less species diversity results in less a. oxygen b. food c. drinkable water d. all of the above

2. sketch the inside of the bean nodule, and describe or label what you observed with the hand lens.

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.