Answer:
D
Explanation:
Atoms and molecules are the smallest units of matter.
Substances made from two or more different elements are a compound
The answer is A, as most sewage treatment plants use bacteria to break down and remove nutrients. The main water pollution problem caused by sewage effluent is eutrophication, related to the release of nutrients into rivers and lakes. Nutrients such as nitrogen and phosphorus ions result in high algal growth. Some algal blooms release toxins, and algal blooms also disrupt the natural dissolved oxygen concentration cycles. Fish kills are often because eutrophication has resulted in anoxic conditions.
Anyway, wastewater treatment plants utilise bacteria to facilitate nitrification or denitrification, which removes ammonia and nitrates/nitrites, respectively.

velocity is a vector so it has a magnitude and direction so the answer would be B
The correct answer is option 4, that is, GCGATT.
Complementary strand refers to either of the two chains, which forms a double helix of DNA, with corresponding positions on the two chains comprising of a pair of complementary bases. It is a section of one nucleic acid, which is bonded to another by an alignment of base pairs.
In nature, complementarity refers to the base principle of DNA transcription and replication as it is a characteristic shared between the two RNA or DNA sequences, such that when they are arranged antiparallel to each other, the nucleotide bases at each position in the sequences will be complementary.