Iron-deficiency anemia can cause fatigue (tiredness), shortness of breath, chest pain, and other symptoms. Severe iron-deficiency anemia can lead to heart problems, infections, problems with growth and development in children, and other complications.
Semantics is the study of meaning. It is a wide subject within the general study of language. An understanding of semantics is essential to the study of language acquisition (how language users acquire a sense of meaning, as speakers and writers, listeners and readers) and of language change (how meanings alter over time).
Topic - Topic / Topics. 1  In topic-based authoring, a topic is a discrete piece of content that is about a specific subject, has an identifiable purpose, and can stand alone. 2  Topic (chocolate bar), a brand of confectionery bar. 3  Topic (linguistics), the information motivating a sentence or clause's structure.