Assertion (A): Saliva contains the enzyme amylase. Reason (R): Amylase begins the digestion of starch in the mouth. MCQ with Answer and Explanation

Explanation:
Xylem is a complex permanent tissue responsible for the unidirectional upward transport of water and dissolved minerals from the roots to the aerial parts of the plant. Phloem is the vascular tissue responsible for the translocation of organic nutrients (primarily sucrose) from sources (leaves) to sinks (roots, fruits), which can be bidirectional. Cambium (vascular and cork) is a lateral meristem responsible for secondary growth (increase in girth); primary growth (increase in length) is driven by apical meristems. Thus, statements 1 and 2 are correct.

Explanation:
Hemoglobin is a red, iron-containing protein in red blood cells (erythrocytes) that reversibly binds oxygen to form oxyhemoglobin. Each molecule has four heme groups, each binding one O₂ molecule. Hemocyanin (copper-based) is found in some invertebrates. Myoglobin stores oxygen in muscles. Cytochromes are electron carriers in respiration. Hemoglobin also transports CO₂ as carbaminohemoglobin.

Explanation:
Bacteria are prokaryotes that primarily reproduce asexually through binary fission, a process where a single cell divides into two identical daughter cells. Fungi reproduce both sexually and asexually, but asexual reproduction commonly occurs through the formation and dispersal of spores (like conidia or sporangiospores). Viruses are obligate intracellular parasites; they lack the metabolic machinery for independent reproduction and must hijack a host cell's machinery to replicate. Thus, statements 1 and 2 are correct.