1. assume/ verb /əˈsjuːm/
to accept something to be true without question or proof.
e.g. Let's assume (that) they're coming and make plans on that basis.
2. diameter/ noun /daɪˈæm.ɪ.tər/
  (the length of) a straight line that reaches from one point on the edge of a round shape or object, through its centre, to a point on the opposite edge.
  e.g. The diameter measures twice the radius.
3. ecosystem/ noun /ˈiː.kəʊˌsɪs.təm/
  all the living things in an area and the way they affect each other and the environment.
  e.g. Pollution can have disastrous effects on the delicately balanced ecosystem.
4. emerge/ verb /ɪˈmɜːdʒ/
  to appear by coming out of something or out from behind something.
  e.g. She emerged from the sea, blue with cold.
  to come to the end of a difficult period or experience.
  e.g. The Prince emerged unscathed from the scandal.
5. frontier/ noun /frʌnˈtɪər/
  a border between two countries, or (especially in the past in the United States) a border between land used to grow crops where people live and wild land.
  e.g. Nepal has frontiers with both India and China.
6. giant/ noun /ˈdʒaɪ.ənt/
  someone who is taller or larger than usual.
7. limb/ noun /lɪm/
  an arm or leg of a person or animal, or a large branch of a tree.
e.g. The accident victims mostly had injuries to their lower limbs (= legs).
8. manage/ verb /ˈmæn.ɪdʒ/
  to succeed in doing something, especially something difficult.
  e.g. I only just managed to finish on time.
9. penetrate/ verb /ˈpen.ɪ.treɪt/
  to move into or through something.
  e.g. In a normal winter, the frost penetrates deeply enough to kill off insect eggs in the soil.
  to succeed in becoming part of an organization, etc. and working within it.
  e.g. The organization had been penetrated by a spy.
  to reach or affect something.
  e.g. These changes had not yet penetrated as far west as the mountains of Merioneth.
10. rot/ verb/ rɑːt/
   to (cause something to) decay.
   e.g. The fruit had been left to rot on the trees.
11. alert/ adjective /əˈlɜːt/
   quick to see, understand and act in a particular situation.
   e.g. A couple of alert readers wrote in to the paper pointing out the mistake.
   alertness/ noun /əˈlɜːt.nəs/
12. bush/ noun/ bʊʃ/
   a plant with many small branches growing either directly from the ground or from a hard woody stem, giving the plant a rounded shape.
   a large amount of hair.
   e.g. The baby was born with a surprising bush of black hair.
13. cylinder/ noun /ˈsɪl.ɪn.dər/
   a solid or hollow tube with long straight sides and two circular ends the same size, or an object shaped like this, often used as a container.
   e.g. Deep-sea divers carry cylinders (= containers) of oxygen on their backs.
14. desperate/ adjective /ˈdes.pər.ət/
   very serious or bad.
   e.g. The situation is desperate - we have no food, very little water and no medical supplies.
   very great or extreme.
   e.g. The earthquake survivors are in desperate need of help.
15. foliage/ noun /ˈfəʊ.li.ɪdʒ/
   the leaves of a plant or tree, or leaves on the stems or branches on which they are growing.
   e.g. The dense foliage overhead almost blocked out the sun.
16. gap/ noun /ɡæp/
   an empty space or opening in the middle of something or between two things.
   e.g. The children squeezed through a gap in the wall.
   gap in the market
   an opportunity for a product or service that does not already exist.
   e.g. There is a gap in the magazine market that needs to be filled.
17. grab/ verb /ɡræb/
   to take hold of something or someone suddenly and roughly.
   e.g. He grabbed (hold of) his child's arm to stop her from running into the road.
18. gravity/ noun /ˈɡræv.ɪ.ti/
   the force which attracts objects towards one another, especially the force that makes things fall to the ground.
19. layer/ noun /ˈleɪ.ər/
   a level of material, such as a type of rock or gas, which is different from the material above or below it, or a thin sheet of a substance.
  e.g. There was a thin layer of oil on the surface of the water.
20. lean/ verb /liːn/
   to (cause to) slope in one direction, or to move the top part of the body in a particular direction.
   e.g. She leaned forward and whispered something in my ear.
  lean (sth) against/on sth
lean sth against/on sth
21. leap /verb /liːp/
   to make a large jump or sudden movement, usually from one place to another.
   e.g. He leapt out of his car and ran towards the house.
22. shrug/ verb /ʃrʌɡ/
   to raise your shoulders and then lower them in order to say you do not know or are not interested.
   e.g. "Where's Dad?" "How should I know?" replied my brother, shrugging.
23. swing/ verb /swɪŋ/
   to move easily and without interruption backwards and forwards or from one side to the other, especially from a fixed point, or to cause something or someone to do this.
   e.g. He walked briskly along the path swinging his rolled-up umbrella.
   to change.
   e.g. His mood swings between elation and despair.
24. tangle/ noun /ˈtæŋ.ɡl̩/
   an untidy mass of things that are not in a state of order, or a state of confusion or difficulty.
   e.g. A tangle of wires.
25. work/ noun /wɝːk/
   an activity, such as a job, which a person uses physical or mental effort to do, usually for money.
   e.g. Carrying heavy loads around all day is hard work.
   the material used by someone at work, or what they produce.
   e.g. All the furniture is the work of residents here.