The process by which plants shed their leaves is called: MCQ with Answer and Explanation

Explanation:
The kidneys are the primary excretory organs, filtering blood through nephrons to remove waste products and excess water, forming urine. The liver is a multifunctional organ that produces bile, which is stored in the gall bladder and released into the small intestine to emulsify fats, aiding in their digestion. The spleen is a lymphoid organ involved in filtering blood and immune responses; it does not produce digestive enzymes (the pancreas does). Thus, statements 1 and 2 are correct.

Explanation:
The corpus luteum, formed from the ruptured follicle after ovulation, secretes progesterone (and some estrogen) which prepares the endometrium for implantation and maintains early pregnancy until the placenta takes over (around 8-10 weeks). hCG, produced by the placenta, maintains the corpus luteum. Progesterone is crucial for maintaining the uterine lining.

Explanation:
Mature human RBCs have a lifespan of approximately 120 days, after which they are phagocytosed by macrophages in the spleen and liver. They lack nuclei and organelles, thus cannot repair themselves. New RBCs are produced in the bone marrow at a rate of about 2 million per second. Erythropoietin stimulates RBC production.