The chemical composition of the gases surrounding the Earth has changed substantially over the past 4 billion years. One notable change was due to the emergence of photosynthetic organisms. The process of photosynthesis increased the amount of what gas in the atmosphere?       

WHICH OF THE FOLLOWING PROVIDES THE BEST EXAMPLE OF ANALOGOUS STRUCTURES RESULTING IN CONVERGENT EVOLUTION

The only mechanism of evolution that leads to adaptation is

Which of the following is TRUE about The Cambrian explosion?

Which of the following was NOT a distinct novel step in evolution in eukaryotes?

PRE-ZYGOTIC BARRIERS CAN INCLUDE

The presence of mitochondria and chloropplasts in eukaryotes can best be explained by

The diversity of marsupials, but the presence of few other (placental) mammals in Australia can be explained by 

What alerts the police to the body hidden in the wall?

What is the difference between the second cat that the narrator owns and the first cat described in the story?