阅读短文，下列问题
Jane Goodall is a famous scientist. For more than 40 years, Goodall lived mostly in Tanzania in East Africa, studying chimpanzees.
As a young child, Jane Goodall was interested in animals. She grew up in the English countryside and was always climbing trees or riding horses.
When Jane was 23, she got a chance to go to Africa even though she had never been to college，she got a job with a famous scientist named Louis Leakey.
One day Louis Leakey said he needed a volunteer. He needed someone to go to a lake in Tanzania to study a kind of chimpanzees. Jane was excited.
On July 16,1960, she began her exploration（探索）. At first, the chimpanzees ran away from Jane. But with time passing，they got used to her being around.
Every day，Jane would follow the chimpanzees，taking notes on their behavior. She learned many new things about chimpanzees. She watched how a chimpanzee made a tool. She learned how some chimpanzees became good leaders. She watched how mother chimpanzees raised their children. She watched animals get angry and get upset. She wrote everything down so others would understand animals as she did. She learned that if you pay really close attention to animals，you will understand what they are “saying”.
组溶液，不用试剂也能鉴别开来的是