Why did Ms. Campbell give Robin more lines in the play than us?
You need to use <u />us here, because <em>us </em>is an objective pronoun (and you need to use an indirect object here), and we is used to denote a subject.
Teens can start an organization, volunteer, donate, etc.
I think it is the third one but im not 100% sure
Global warming
Rising global temperatures caused by CO2 emissions heat the water, reducing its oxygen content.
Deforestation
Felling forests can exhaust water resources and generate organic residue which becomes a breeding ground for harmful bacteria.
Industry, agriculture and livestock farming
Chemical dumping from these sectors is one of the main causes of eutrophication of water.
Rubbish and faecal water dumping
The UN says that more than 80% of the world's sewage finds its way into seas and rivers untreated.
Maritime traffic
Much of the plastic pollution in the ocean comes from fishing boats, tankers and cargo shipping.
Fuel spillages
The transportation and storage of oil and its derivatives is subject to leakage that pollutes our water resources.
EFFECTS OF WATER POLLUTION
Deteriorating water quality is damaging the environment, health conditions and the global economy. The president of the World Bank, David Malpass, warns of the economic impact: "Deteriorating water quality is stalling economic growth and exacerbating poverty in many countries". The explanation is that, when biological oxygen demand — the indicator that measures the organic pollution found in water — exceeds a certain threshold, the growth in the Gross Domestic Product (GDP) of the regions within the associated water basins falls by a third. In addition, here are some of the other consequences:
Destruction of biodiversity. Water pollution depletes aquatic ecosystems and triggers unbridled proliferation of phytoplankton in lakes — eutrophication —.
Contamination of the food chain. Fishing in polluted waters and the use of waste water for livestock farming and agriculture can introduce toxins into foods which are harmful to our health when eaten.
Lack of potable water. The UN says that billions of people around the world have no access to clean water to drink or sanitation, particularly in rural areas.
Disease. The WHO estimates that about 2 billion people have no option but to drink water contaminated by excrement, exposing them to diseases such as cholera, hepatitis A and dysentery.
Infant mortality. According to the UN, diarrhoeal diseases linked to lack of hygiene cause the death of about 1,000 children a day worldwide.
