Explanation

Sex ratio is the ratio of males to females in a population Types of Sex Ratio In most species, sex ratio varies according to the age profile of the population It is generally divided into four sub-divisions (i) Primary sex ratio – Ratio at fertilisation (ii) Secondary sex ratio – Ratio of birth (iii) Tertiary sex ratio – Ratio of sexually active organisms. Also called adult sex ratio and abbreviated to ASR. ASR is defined as the proportion of adults in a population that are male (iv) Quaternary sex ratio – Ratio in post-reproductive organisms