13A) Around 10 metres in length, a herbivorous dinosaur that had a broad heavy tail, lizard like teeth and thumbs which developed into spikes? I _ U _ N _ D _ N?
23A) A miner's pick, also a clamp like sectionj of a lathe to which work is fixed while being turned? M _ N _ R _L?
31A) An early name for a type of nuclear reactor? A _ O _ I _ P _ L _ ? Atomic?