Answer:
Gravity.
Explanation:
Gravity is what causes stuff to fall. It also keeps us on the ground, If there were no gravity, life wouldn’t exist as we know it today. Brainliest please! I need brainlest in order to keep answering questions!!
Answer:
DNA may be taken up by bacterial cells and be active.
Explanation:
To understand Avery, MacLeod, and McCarty's experiment, it is important to know Frederick Griffith's precursor experiment. The microbiologist worked at the British Ministry of Health's Pathology Laboratory with pneumococci (commonly known as the bacterium Streptococcus pneumoniae, then known as Pneumococcus, which causes pneumonia), which were previously classified into several types. When cultured in petri dishes in the laboratory, the pneumococci that synthesize their capsules generate 'smooth' colonies. Subcutaneous injection of liquid culture of these pneumococci into mice causes their death. However, in vitro culture also allows the emergence of rough colonies', whose bacteria have lost the ability to synthesize mucopolysaccharide (and therefore have no capsules). Rough mutants could no longer be classified with sera and, moreover, lost their virulence: mice inoculated with them remained alive, unlike inoculated with smooth pneumococci.
The nature of Griffith's transforming principle remained unclear until the work of Avery, MacLeod, and McCarty. They repeated the in vitro transformation of pneumococci at the Rockfeller Institute for Medical Research, but replaced heat-dead cells with a purified fraction of smooth bacterial extract (unable to cause disease alone) and treated the material with different enzymes, each capable of destroying a specific type of macromolecule. Experience has shown that this fraction retained its transforming capacity when treated with protein or RNA degrading enzymes, but lost that ability when treated with DNA degrading enzymes. These results indicated that the chemical nature of the 'transforming principle' was DNA.
Thus, we can conclude that in addition to identifying genetic material, Avery, MacLeod and McCarty experiments with different strains of Streptococcus pneumoniae demonstrated that DNA can be absorbed by bacterial cells and be active.
The effect nervous system has on the heart rate is
Stimulation by parasympathetic nerves causes the heart rate to slow down.
The two branches of the autonomic (involuntary) nervous system regulate heart rate. The parasympathetic nervous system and the sympathetic nervous system (SNS and PNS) (PNS). To increase heart rate, the sympathetic nervous system (SNS) produces the catecholamines epinephrine and norepinephrine. The hormone acetylcholine is released by the parasympathetic nervous system (PNS) to reduce the heart rate. Your heart rate may briefly increase due to stress, coffee, and excitement, whereas it may temporarily decrease due to meditation or deep, steady breathing. Any amount of exercise will raise your heart rate, which will stay up as long as you keep exercising.
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