Answer:
- ice formed thousands of years ago
- tree rings.
Step-by-step explanation:
The correct answers are ice formed thousands of years ago and tree rings.
- Fossilized pollen can be used to determine the type of plants that were present in a particular area at a particular time.It can be used to infer the climate of the area at that time but does not provide direct information about the air temperature.
- Chemical isotopes in foraminifera shells can be used to determine the ocean temperature at the time the shells were formed but they cannot be used to determine the air temperature.
- Ice formed thousands of years ago contains trapped air bubbles. The composition of these air bubbles can be used to determine the air temperature at the time the ice was formed.
- Tree rings can be used to determine the age of a tree and the climate conditions that the tree experienced during its lifetime. The width of tree rings is related to the amount of growth that the tree experienced in a particular year. In years with warm temperatures and abundant rainfall, trees tend to grow wider rings. In years with cold temperatures and/or drought, trees tend to grow narrower rings. Therefore, tree rings can be used to infer the air temperature at the time the tree rings were formed.
Scientists study ice formed thousands of years ago and tree rings to determine the air temperature at the time they were formed.