Lungs sac-like structures of varying complexity where blood and air exchange oxygen and carbon dioxide; connected to the outside by a series of tubes and a small opening.
Leukocytes white blood cells; primarily engaged in fighting infection. leuk=white, colorless
Lichens autotrophic organisms composed of a fungus and a photosynthetic unicellular organism (e.g., a cyanobacterium蓝藻 or alga) in a symbiotic relationship; are resistant to extremes of cold and drought and can grow in marginal areas such as arctic tundra（苔原）. 地衣
Light reactions the photosynthetic process in which solar energy is harvested and transferred into the chemical bonds of ATP; can occur only in light.
Kreb‘s cycle biochemical cycle in cellular aerobic Metabolism where acetyl CoA is combined with oxaloacetate（草酰乙酸） to form citric acid; the resulting citric acid is converted into a number of other chemicals, eventually reforming oxaloacetate; NADH, some ATP, and FADH2 are produced and carbon dioxide is released
Jurassic period middle period of the Mesozoic era, between 185-135 million years ago. Characterized by the (possible) origin of angiosperms and the continued split of the worldwide supercontinent of pangea（泛大陆）
Kingdoms five broad taxonomic categories (Monera, protista, plantae, Fungi, animalia) into which organisms are grouped, based on common characteristics.
Lateral roots roots extending away from the main (or taproot) root.
Leaf veins vascular tissue in leaves, arranged in a net-like network in Dicots, and running parallel to each other in Monocots.
Large intestine
consists of the cecum盲肠, appendix, colon结肠, and rectum 直肠; absorbs some nutrients, but mainly prepares Feces 粪便 for elimination small intestine
Karyotype the chromosomal characteristics of a cell; also, a representation of the Chromosomes aligned in pairs. 染色体组型, 核型
Kidney stones crystallized deposits of excess wastes such as uric acid, calcium, and magnesium that may form in the kidney stones.
Lymphocytes white blood cells that arise in the bone marrow（髓） and mediate the immune response; include T cells and B cells.
Lymph
Interstitial（组织间隙的） fluid
in the lymphatic system. From
Latin lympha [water spirit]
Lymphatic system a network of glands and vessels that drain Interstitial fluid from body tissues and return it to the Circulatory system.

Logistic growth model a model of population growth in which the population initially grows at an Exponential rate until it is limited by some factor; then, the population enters a slower growth phase and eventually stabilizes.