Answer:B) homologous chromosomes trade pieces of dna
Explanation:
Crossing over occurs between two homologous chromosome of sisters chromatid. Crossing over leads to exchange of genetic material between the two sister chromatids leading to recombination.
They are used for them to adapt to the environment
Guard cells use osmotic pressure to open and close stomata, allowing plants to regulate the amount of water and solutes within them. In order for plants to produce energy and maintain cellular function, their cells undergo the highly intricate process of photosynthesis
