Analysis of air bubbles trapped in fossils, such as in fossil amber, show that our air in earliest times contained about 35% oxygen. Today, the average oxygen content of our air is approximately 20%. In some larger, more polluted cities, oxygen content in the air has been measured at 12 - 15%.
There are 297 words which start with 'pen'. 3 letter words starting with 'pen': pen. 4 letter words starting with 'pen': pend. pens.
Label 10 Words that Start with W Label each of the words that start with W on this worksheet. The words are: watermelon, wagon, walrus, whale, wheel, wasp, woman, wand, web, world. Go to the answers. Draw and Write W Words The student writes and draws pictures of eight words that start with the letter W.