The two, who graduated from their high schools last week, plan to pursue careers in science.
Rosensteel said he knew before the internship that he wanted to have a career in science but he had not decided on the specialty, he said.
"It reconfirmed what I thought science would be like," he said.
Since he was about 3, Rosensteel has wanted to be a paleontologist so he could study dinosaurs, he said.
Now he is hoping to be a paleontologist working with ancient DNA, he said.
The internships ran from June 2003 to earlier this month. Rosensteel will continue to work as an intern until the end of the summer, when he will start classes at University of Maryland Baltimore County.
Both worked in the labs for about 40 hours a week last summer and about 15 hours a week during the school year.
Brucksch, who plans to attend University of Maryland College Park in the fall, said her favorite part of the internship was working in a professional lab with experts in the field.
"It provides hands-on experience which can open a lot of doors for me in college," she said.
As part of her work, she compared the DNA of Africa's forest and savanna elephants, hoping to learn more about how the species differ.
She also worked on a project that consumed most of Rosensteel's time in the labs: Studying feline leukemia.
By examining the frozen DNA from cats with leukemia, it is hoped that a better understanding of the virus and the cats themselves will develop, he said.
Rosensteel and Brucksch were recognized at the June 1 Washington County Board of Education meeting. Both told board members about their projects.
Valerie Novak, principal of Smithsburg High, said she was impressed by the presentation, particularly with how the students have been able to apply their science knowledge. Brucksch always has been an exceptional student, she said.