Answer:
Answer is Sinoatrial node, SA.
Explanation:
The sinoatrial node, SA, is known to be a group of cells which are found at the top of the heart.
The electrical signal that is initiated by the sinoatrial node bring about or stimulates the atria and then the ventricle of the heart.
It should be noted that, the sinoatrial node are regarded as the pacemaker cells.
Answer:
Temperature is the measure of the average energy of motion of all the particles present in a substance because particles of a substance moves due to the presence of kinetic energy.
Explanation:
Kinetic energy is a type of energy that is present in an object due to its motion. When temperature of a substance is increased, the particles absorb heat energy from surrounding environment and starts motion. This motion of particles due to the absorption of heat energy is called kinetic energy. So that's why temperature is considered as a tool to measure average energy of a motion.
The correct answer is: a. A site in DNA that recruits the RNA Polymerase
Promoters are regions of DNA molecule located near the transcription start codons of genes, usually upstream on the DNA with the function to initiate DNA transcription. Promoters contain specific DNA sequences (e.g. TATA boxes) that are binding sites for the enzyme RNA polymerase and transcription factors that recruit RNA polymerase. Transcription factors can regulate gene expression and act as activators or repressors depending on sequences that attach to specific promoters.
Direct observation is an observation you make first hand. It is something you see with your own eyes and observe yourself.
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