The pyramid of energy shows the flow of energy at successive trophic levels. Energy decreases as it moves up (about 10% transfer), so the pyramid is always upright. Pyramids of number and biomass may be inverted in some ecosystems (e.g., parasitic food chains, pond ecosystem), but the energy pyramid never is, according to the second law of thermodynamics.
Explanation:
Louis Pasteur developed the first vaccine against rabies in 1885, using a weakened strain of the virus. He also invented pasteurization and made significant contributions to microbiology, disproving spontaneous generation. Jenner developed smallpox vaccine. Salk developed polio vaccine. BCG for TB was developed later. Pasteur's work laid the groundwork for modern immunology.
Explanation:
Oxytocin, released from the posterior pituitary, increases the frequency and strength of uterine contractions during labor via positive feedback. Prolactin stimulates milk production, estrogen helps uterine growth, relaxin relaxes pelvic ligaments.
Explanation:
The epididymis is a coiled tube on the posterior surface of the testis where spermatozoa undergo maturation and are stored until ejaculation. Sperm acquire motility here. Seminal vesicles and prostate gland secrete seminal fluid. Vas deferens transports sperm from epididymis to ejaculatory duct. Testes produce sperm and testosterone. Sperm maturation includes gaining ability to fertilize.
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