The correct answer is c. smoke stacks.
Smoke stacks are chimneys or funnel shaped structures which emit smoke from a factory, vehicles and industrial set ups. Smoke stacks mostly discharge carbon dioxide and water vapor and oxides of nitrogen into the atmosphere. The exhaust released from smoke stacks cause air pollution. Air pollution can cause ailments like asthma and cancer. Thus, smoke stacks are not a source of water pollution.
Answer:
The endoplasmic reticulum can either be smooth or rough, and in general its function is to produce proteins for the rest of the cell to function. The rough endoplasmic reticulum has on it ribosomes, which are small, round organelles whose function it is to make those proteins.
They are considered organic molecules because the monomer which make proteins are amino acids which are organic compounds.
The answer is vitamin D. This is actually a group of vitamins of similar molecular structure responsible for facilitating increased absorption of calcium, magnesium and phosphate from the gut. The most important of the vitamin D compounds are vitamin D3 and D2. While vitamin D can be obtained from your diet and supplements, the major source of vitamin D is from a chemical reaction dependent on skin exposure to the sun.
