Final answer:
True. Lake sediment cores can be used to identify drought conditions from gypsum and oxygen isotope measurements and deforestation from pollen records.
Step-by-step explanation:
True. Lake sediment cores can be used as a proxy to identify drought conditions and deforestation. Gypsum and oxygen isotope measurements can help determine drought conditions, while pollen records can indicate deforestation. By analyzing these indicators in sediment cores, scientists can infer past climate and environmental changes. For example, a decrease in gypsum and certain types of pollen can suggest periods of drought and deforestation, respectively.