阅读材料并读图：我们的制度之所以成为民主政治，因为政权是在全体公民手中，而不是在少数人手中。——伯里克利请回答：（1）伯里克利是古代欧洲哪一城邦国家的执政官？他执政时期雅典城邦政治更加民主化，表现在哪些方    面？                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       （2）你是如何理解伯里克利所说“政权是在全体公民手中，而不是在少数人手中”的？                                                                                                                                                                                                                                                                                                                          （3）上图反映的是哪个国家的什么权力机构？该国的政权主要掌握在什么人手中？