Which is the primary source of stem thickening in plants?

Which is a genetic engineering advancement directly related to a career in biotechnology? 1) improving solar energy collection 2) transporting textiles at higher rates 3)creating crop foods that resist insect pests 4)repairing historical sites with quality materials

Fill in the blank with the correct sphere label. a: ⇒ geosphere b: ⇒ biosphere c: ⇒ hydrosphere

Which correctly describes crossing over ?