Our present to you is the science of gifts. First, we investigate the health benefits of donating blood, and find out about the predator sharing a feast of food in the Arctic. We are then joined in the studio by physicist Dr Krishma Singal from Rice University, who unravels the soft-matter physics and brilliant engineering potential of knitting. Next, we discuss the reputation of piranhas, enquire about the uniqueness of our sneezes, and break down how salting roads makes them safer in the winter.