12. biology is the study of living things. carbon is the element that makes life possible. why is carbon so special that it is required for life? [] it is a positively charged ion needed in reactions. [] it has 4 valence electrons, so it can make 4 strong bonds with other atoms. [] it is a polar molecule, which makes it have a high heat capacity. [] because it has 4 valence electrons, it is small and only makes small compounds.

Because carbon is the base of living things. Consider the word "carbohydrates." The prefix carbo- is equal to carbon. Most things are bonded to carbon.

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B and silicon can work the same way. hope i helped!!!

advantage of using stem cells in medical research:

1.       it provides medical benefits in the fields of therapeutic cloning and regenerative medicine.

2. it provides great potential for discovering treatments and cures to a variety of diseases including parkinson disease, spinal cord injuries, diabetes, alzheimer’s disease and many more.

3. limbs and organ could be grown in lab from stem cells and then used in transplant or treat illness.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.