The hormone that decreases blood glucose by promoting its uptake into cells is: MCQ with Answer and Explanation

Explanation:
Insulin, secreted by the pancreas, promotes cellular glucose uptake, lowering blood sugar levels. Adrenaline (epinephrine) from the adrenal medulla triggers the fight-or-flight response, increasing heart rate and energy supply. Thyroxine, produced by the thyroid gland, requires iodine as an essential component for its synthesis; iodine deficiency causes goiter. All statements are correct.

Explanation:
Mitochondria and chloroplasts contain their own DNA and ribosomes (70S) and can replicate by binary fission, a feature supporting their endosymbiotic origin. Golgi apparatus, lysosomes, and rough ER cannot self-replicate; they are part of the endomembrane system and arise from pre-existing membranes. Mitochondria are thus semi-autonomous organelles.

Explanation:
Genetic variation within a population provides the raw material upon which evolutionary forces act; without variation, evolution cannot occur. Natural selection acts directly on the phenotype (observable traits) of an organism, determining its survival and reproductive success. However, evolution is a population-level phenomenon; it involves changes in allele frequencies over generations, not changes occurring within a single individual's lifetime. Thus, statements 1 and 2 are correct.