lichens

"Astronomers study symbiotic stars to understand how two stars can orbit each other and exchange matter. "

"My friend told me there was something in the box, but I didn't know what it was yet. "

"The sunflower's bright yellow petals attracted many bees. "

"The plants gradually grew taller over the summer. "

"The abandoned building, covered in graffiti and broken windows, was an unsightly addition to the neighborhood. "

"His sleeves had patches on the elbows where different fabric had been sewn on to replace material that had worn away."

"The school hallways were covered in graffiti. "

"The spreads on the sandwiches at the picnic included peanut butter and jelly. "

"The child's associations with the park were mostly happy, filled with memories of playing with friends. "

"He covered the baby with a blanket."

"The lightning caused thunder."

"Scientists study different organisms, such as bacteria and plants, to learn about life on Earth. "