Many (not all) of the greatest scientific discoveries found till this day have been discovered under unethical methods or proceedings. Unfortunately, many as well have been discovered through unethical experimentations for research purposes. However, now there are associations dedicated to approve scientific research ideas before they undergo proceedings of the scientific method in order to prevent more unethical research being done. Within the science community, we are greatful for what we've come to know... however, greatly disappointed with how many of those discoveries came about. Therefore, thanks to these associations, there should be no more unethical practices, experimentations, or research (although there are still quite a few going on in the world). That being said, yes... I believe scientists should definitely be ethical with their work. Otherwise, there will be consequences they shall face.
The answer to this Q is voluntary
An example of a parasite would be a worm in your intestine
There are two things that cause ocean water to become denser, and those are b) the salinity of water and low temperatures.
The more salt there is, the denser the water will be - take the lake Dead Sea in Israel, Jordan, and Palestine for example.
And the lower the temperature, again, the denser the water will be - the deeper you go into an ocean, it will be more difficult to move around due to density and other things.
Reported or indirect speech is usually used to talk about the past, so we normally change the tense of the words spoken. We use reporting verbs like 'say', 'tell', 'ask', and we may use the word 'that' to introduce the reported words. Inverted commas are not used.
