The reason why olive tree has been associated with the Tur mountain is that this tree first grew on that mountain. Some people have said that it was the first tree to grow on earth after the great Deluge in the days of Sayyidna Nuh (علیہ السلام) . (Mazhari)
Then there is a mention of the blessings and the numerous gifts which Allah has provided for the benefitof ankind so that they may ponder and worship Him. The words of the verse are وَإِنَّ لَكُمْ فِي الْأَنْعَامِ لَعِبْرَةً (And indeed there is a sure lesson in the cattle for you - 23:21). The lesson to which this verse refers has been described further in the words نُّسْقِيكُم مِّمَّا فِي بُطُونِهَا (We give you a drink from that which lies in their bellies - 23:21). Some of the ways in which the cattle serve mankind are that they provide milk which is a very clear and nourishing food; every part of their body is put to some use, and their wool, hides, intestines etc. are all utilized, in industries which support a country's economy, the meat of the animals, which are halal (permissible) is a favourite food for all men. وَمِنْهَا تَأْكُلُونَ (and of them you eat - 23:21). And finally they are used, together with ships, as mounts and as means of transporting goods from one place to another.