Q: Sheep Challenge Evolution A species of sheep lives on the Scottish island of Hirta. Hirta has plenty of grass for the sheep to eat, and no natural predators of the sheep live on the island. Some sheep have dark wool, and some have light wool. The sheep with dark wool tend to be much larger and stronger than the sheep with light wool. However, researchers have found that in the last 20 years, the sheep with light wool have increased in number. Usually, strength and size help animals survive and breed. On Hirta, sheep with light wool outnumber sheep with dark wool because sheep with light wool OPTIONS:
- produce more wool
- have a more restricted diet
- produce fewer offspring each year
- have a better chance of surviving and reproducing
A: have a better chance of surviving and reproducing

Q: A crop of corn plants is genetically modified so that the plants produce a natural pesticide. People are concerned that these corn plants might transfer modified genetic material to other plants. Which of the following is the best way to further modify the plants to prevent them from transferring their genetic materials to other plants? OPTIONS:
- changing the plants so they do not make pollen
- changing the plants so they do not harm insects
- changing the plants so they cannot produce nutrients
- changing the plants so they cannot be easily identified
A: changing the plants so they do not make pollen

Q: A chemical property of a mineral is evident if the mineral OPTIONS:
- breaks easily when struck with a hammer
- bubbles when acid is placed on it
- is easily scratched by a fingernail
- reflects light from its surface
A: bubbles when acid is placed on it

Q: Which event would most likely cause a rapid extinction of organisms? OPTIONS:
- a large asteroid impact
- regional drought
- new glacier formation
- a decrease in the growth of weeds
A:
a large asteroid impact