During which phase of the cell cycle does DNA replication occur? MCQ with Answer and Explanation

Explanation:
Carbohydrates are the body's primary and most readily available source of energy, broken down into glucose for immediate cellular use. Proteins are essential 'body-building' foods, providing amino acids necessary for the growth, repair, and maintenance of tissues, muscles, and enzymes. Fats are essential macronutrients; they provide concentrated energy, are crucial for cell membrane structure, aid in the absorption of fat-soluble vitamins, and provide essential fatty acids. Thus, statements 1 and 2 are correct.

Explanation:
COVID-19 is caused by SARS-CoV-2, a novel coronavirus. Tuberculosis is bacterial (Mycobacterium). Influenza is caused by influenza viruses (Orthomyxoviridae), not coronavirus. Pneumonia can be bacterial or viral, but the question specifies Streptococcus which is bacterial. COVID-19 emerged in 2019, causing a global pandemic, primarily affecting the respiratory system.

Explanation:
A mature embryo sac (female gametophyte) in angiosperms is 7-celled but 8-nucleate: 3 antipodal cells (3 nuclei), 2 synergids (2 nuclei), 1 egg cell (1 nucleus), and 1 central cell with 2 polar nuclei. Thus total 8 haploid nuclei. The central cell is homodiploid (2 polar nuclei). Double fertilization involves these nuclei. This is typical of Polygonum type of development.