Stem cells are what allow planaria to grow and regenerate as the stem cells can change into any of the cells that make up the planaria.
Answer:
Birds can keep themselves warn without any external heat source which is not the case with reptiles and amphibians
Explanation:
Birds are able to generate heat means they are endothermic. They generate heat through various metabolic processes. They have air pockets beneath their feathers to insulate their bodies during cold temperatures. Feathers which are modified reptilian scales help birds to streamline their exterior body and structure feathers in a way that it insulates the body.
1. Enzyme is the molecule that serves to make reactions work. Enzymes are biochemical catalysts that catalyses chemical reactions in a cell by acting on substrates and convert them to products. Their rate of action increases with increase in substrate concentration, reaching optimum when all active sites of the enzyme are engaged.
2. Plastid are the tiny sacs in the cell that may contain starch. Plastid are major cell organelles found in the cells of plants and algae. Plastids are site for the manufacture and storage of important chemical compounds used by the cell. They often contain pigments used in photosynthesis, and the types of pigments present can change or determine cells color.
3. Lysosome are packets within the cell that contain digestive enzymes. Lysosomes are one of many organelles found in animal cells. they are tiny like sacs filled with enzymes that enables the cell to process nutrients. They contain digestive enzymes which helps in the digestion of worn out organelles, food particles and engulfed viruses or bacteria.
4. Mitochondrion is a structure within a cell that is responsible for production of energy. Energy in a cell is produced through a process of cellular respiration which involves use of nutrients with oxygen gas to yield energy inform of ATP, water and carbon dioxide. The process takes place in the mitochondrion where oxygen acts as proton acceptor in the electron transport chain coupled by production of energy.
5. An Organelle is a small structure that serves specialized functions. A cell is made up of various organelles that help it perform its functions. Each organelle is specialized to perform as specific function different from other organelles, for example ribosomes is an organelle involved in the manufacture of proteins.
6. Golgi apparatus are group of flattened sacs that package and export materials out of the cell. Golgi apparatus also called golgi complex or golgi body, is a membrane bound organelle in eukaryotic cells that is made up by a series of flattened, stacked pouches called cisternae. They are responsible for transporting, modifying, and packaging proteins and lipids into vesicles.
7. Vesicles are tiny sacs connected to the Endoplasmic reticulum and Golgi apparatus. Vesicles are small structures within a cell, or extracellular, consisting of fluid enclosed by a lipid bi-layer. they form naturally during the process of secretion (exocytosis), uptake (endocytosis) and transport of materials within the cytoplasm.
