Which of the following is a correct statement about the human skeleton? MCQ with Answer and Explanation

Explanation:
Heredity (inheritance) is the transmission of genetic information and traits from parents to offspring through genes. Variation refers to differences among individuals, evolution is the change in heritable traits over generations, and mutation is a change in DNA sequence. Mendel's laws describe the patterns of heredity. Genes are the units of heredity.

Explanation:
Adiponectin is an abundant protein hormone secreted by adipose tissue. Uniquely, its plasma levels are inversely correlated with body fat percentage; obese individuals have lower levels. Its primary functions are highly beneficial for metabolic health: it enhances insulin sensitivity in the liver and muscles, promotes the oxidation of fatty acids (reducing fat accumulation), inhibits glucose production by the liver, and has potent anti-inflammatory and anti-atherogenic effects on the blood vessels. Low levels of adiponectin are associated with insulin resistance, type 2 diabetes, and cardiovascular disease.

Explanation:
The stratospheric ozone layer acts as a vital shield, absorbing the majority of the sun's harmful ultraviolet (UV-B and UV-C) radiation, protecting life on Earth. Greenhouse gases (like CO2, methane, water vapor) absorb and re-emit infrared radiation, trapping heat in the troposphere and maintaining Earth's temperature (the greenhouse effect). Acid rain, containing sulfuric and nitric acids, is highly detrimental; it leaches essential nutrients from the soil, releases toxic aluminum, and damages plant life, reducing soil fertility. Thus, statements 1 and 2 are correct.