Which statement about population growth rate is true?

• A. It is always positive
• B. It is calculated yearly
• C. It measures population density
• D. It can be a negative number

Answer: (D)

Population growth rate shows how fast a population changes in size over a given period, usually expressed as a percentage per year. Because births, deaths, and migration vary, the rate can be positive when there are more births than deaths and net in-migration, zero when these factors balance, or negative when deaths and net out-migration exceed births and net in-migration. So it can be a negative number, indicating a shrinking population. The other statements don’t hold universally: it isn’t always positive, the interval it’s calculated over isn’t fixed to yearly in all cases, and it doesn’t measure density (that’s about how many individuals live in a given area).