Final answer:
The most significant change contributing to reduced fertility rates in less developed countries is providing educational opportunities for girls and women, leading to fewer children due to a combination of economic empowerment, access to family planning, and advancements in gender equality. correct option is D.
Step-by-step explanation:
The change that most reduced fertility rates in less developed countries is providing more educational opportunities for girls and women. Evidence from many populations shows that when girls and women are educated, they tend to have fewer children. This is due to a combination of factors including greater knowledge of family planning, advancements in gender equality, and better access to contraception. Moreover, education can lead to more economic opportunities, which, along with education, empowers women to have greater control over their reproductive choices.
Improved healthcare, including the introduction of modern medicine and health services, also contributed to reduced fertility rates by lowering infant mortality rates. Once infant survival becomes more assured, families tend to have fewer children. However, access to contraception and family planning education has had highly positive effects on limiting population growth rates and directly influencing fertility rates.