In primary ecological succession on a bare rock (xerarch), the first organisms to colonize the rock are typically: MCQ with Answer and Explanation

Explanation:
Kwashiorkor is a severe form of malnutrition caused by inadequate protein intake despite sufficient calorie consumption. Marasmus results from a severe deficiency of both calories and protein, leading to extreme wasting. Goiter is the enlargement of the thyroid gland caused by iodine deficiency, not iron deficiency (which causes anemia). Thus, statements 1 and 2 are correct.

Explanation:
Active immunity occurs when the body's own immune system is stimulated by an antigen (either through infection or vaccination) to produce its own antibodies and memory cells, providing long-lasting protection. Passive immunity occurs when an individual is directly given pre-formed antibodies (like through mother's milk or antiserum), providing immediate but temporary protection. Vaccination stimulates the body to produce its own immune response, thus providing artificial active immunity, not passive. Thus, statements 1 and 2 are correct.

Explanation:
Hemophilia A is an X-linked recessive bleeding disorder caused by deficiency of factor VIII. Hemophilia B is factor IX deficiency. Anemia is low RBCs, thalassemia abnormal hemoglobin, leukemia cancer of WBCs.