What are the signs of termite activity in a home, particularly in relation to the presence of termite tunnels on walls?

Signs of termite activity in a home include mud tubes or tunnels on walls, floors, or ceilings. These tunnels are typically made of soil and termite saliva, and serve as protective pathways for termites to travel between their nest and food sources. If you notice these tunnels, it may indicate a termite infestation in your home.