Everyday Science

Carrots are rich in beta-carotene, which the body converts into Vitamin A. This vitamin is essential for good vision and immune function, making Vitamin A the correct answer.

The planets visible to the naked eye without a telescope are Mercury, Venus, Mars, Jupiter, and Saturn, totaling five planets. Hence, option C is correct.

Dry ice is the solid form of carbon dioxide (CO2). It sublimates directly from solid to gas at temperatures below -78.5°C, making it commonly used as a cooling agent.

Rectified spirit is a highly concentrated ethanol solution, typically containing about 95% alcohol by volume. This high purity is achieved through repeated distillation, making option B correct.

Biotechnology plays a significant role in food production primarily through fermentation, which is used to produce products like yogurt, cheese, and alcoholic beverages by utilizing microorganisms to transform raw materials.

Lactobacillus is a genus of bacteria used in the fermentation process to make yogurt by converting lactose into lactic acid, which thickens the milk and gives yogurt its characteristic tangy flavor. The other bacteria listed do not play a role in yogurt production and can be harmful.

Diamond is an allotrope of carbon, meaning it is composed entirely of carbon atoms arranged in a crystal lattice, which makes it a single-element substance. Therefore, the correct answer is Carbon.

Fluorine (in the form of fluoride) is essential for the proper formation of teeth as it helps in the development of strong enamel and prevents dental caries.

Vitamin B complex vitamins are found in a variety of foods. Green leafy vegetables are rich sources of several B vitamins, especially folate (B9). Seeds, particularly sunflower seeds, also provide good amounts of some B vitamins like pantothenic acid (B5) and B6, but are not as comprehensive sources as leafy greens. Fresh vegetables and fruits generally contain lower amounts of B complex vitamins. Seafood is an excellent source of certain B vitamins, especially B12, but not all B complex vitamins are abundant in seafood. Therefore, among the given options, green leafy vegetables are considered a good and consistent source of Vitamin B complex.

Human population growth is greatest in developing countries primarily because the birth rate is high, leading to more births than deaths. This results in rapid population increase compared to developed countries where birth rates are generally lower.