Answer:
Explanation:
During a physical change, the arrangement of particles may change but the mass, number of atoms and number of molecules will stay the same. ... During a chemical change, the mass and number of atoms is conserved, but the number of molecules is not always the same. Chemical reactions involve large changes in energy.
Answer: positive feedback loops enhance or amplify changes. this tends to move a system away from its equilibrium state and make it more unstable. Negative feedbacks tend to dampen or buffer changes. this tends to hold a system to some equilibrium state making it more stable.
Explanation:
Answer:
e) All of the answers are correct
Explanation:
The first X-ray picture of DNA taken in 1952 by Rosalind Franklin using the X-ray crystallography technique revealed the helical shape of DNA. Based on this discovery, it was discovered later on that the DNA molecule was made of two chains of nucleotides and at high humidity i.e when exposed to water it becomes long and thin.
During exercise, a number of changes occur to maximise the body's oxygen intake. Firstly our heart rate/ pulse increases. This is due to the heart beating much faster and more forcefully to pump blood faster around the body.
Our breathing rate increases to intake more oxygen and exhale more CO2.
The smooth muscle in our trachea and bronchi relaxes to increase the lumen size thus making breathing easier. Adrenaline may also be released leading further amplifying these changes as well as reducing blood flow to the gut and thus peristalsis occurs at a much slower rate.
Also when we exercise we respire more, producing heat, which must be expelled. This may be done through sweating. Another physiological change that occurs is vasodilation of arterioles closer to the skin to allow more blood to flow closer to the skin, allowing more heat to radiate out.
How organisms change through time
