A common way that humans pollute water is through the addition of nutrients (fertilizers and sewage) to water as nonpoint source pollution. These added materials are full of nitrogen and phosphorus, two nutrients that encourage the growth of aquatic producers, such as algae.
Answer: alpha
Explanation: Alpha particles are fast moving streams of positively charged particles that are shown to be Helium nuclei. They have a mass
number of 4 and an atomic number of 2 and a charge of +2. Alpha particles are represented as 4He2. When 238U92 becomes 234Th90, it emitted a helium nucleus 4He2. The equation for the decay is 238U92 ---> 234Th90 + 4He2.