Matter is not created nor destroyed?

Think about it. An egg and a sperm come together to form a fertilized egg cell, matter is conserved there. This cell uses nutrients and proteins etc. from the mothers body to grow, so matter is also conserved there. Through your life you eat food to grow, matter is conserved again. Living creatures are merely recycled matter

Please tell us who 'they" is, because "they" is wrong.

MATTER is destroyed under the right circumstances, and, under the right circumstances, matter can be created.

Einstein's famous equation, E=MC2 (Ee equals Em Cee Squared) say that matter and energy are the same thing, just in different FORMS, like steam, ice, and liquid are all different forms of water. Therefore, it IS TRUE that ENERGY can never be created nor destroyed -- it can only CHANGE FORM. And MATTER is ONE of the forms the energy can take, according to Einstein. MATTER, though, CAN be destroyed or created under the proper circumstances.

SO, under certain circumstances (like inside a super-collider like at CERN, or deep inside a sun) matter IS destroyed -- the solid form of matter becomes a form of energy, primarily light and heat.

Frankly, people do the ame thing with a piece of paper and a match. When you light the paper on fire with the match, you take the match away and blow it out. But the paper keeps on burning until it is totally consumed. If you do this under scientifically controlled environment, you can first weigh the paper, then weigh the ashes, and you will find out that the ashes weigh less than the paper, thus showing that SOME of the matter of the paper was changed to ENERGY in the form of light, AND into heat that keeps the paper burning even after the match is blown out.

However, living things do NOT create new matter, but instead re-assemble the OLD matter (food, water, proteins, vitamins, etc) into different forms of matter (cells). This is not CREATION of new matter, but is a simply reformation of matter that already exists (food) into a different form of matter (cells).

Plants are rather interesting. Again, they do not CREATE new matter, but convert water and nutrients from the soil into new plant material through a process called PHOTOSYNTHESIS. but the ENERGY they need to do this comes directly from SUNLIGHT. In the process of reforming the matter of the water and nutrients, they actually STORE energy from the sun into the plant cells.

Of course, when an animal eats the plants, the animal converts the plant-matter into animal-matter, and much of the energy needs to do this actually comes from the plants matter itself! The WHOLE IDEA of digestion is to break down one form of matter into another form of matter, and this ALSO release energy. This is ONE of the reasons why OUR bodies are warm -- Our digestive process releases excess energy that our cells never use, and the excess is given off from our bodies as heat.

Oh dear.

Matter is approximately conserved within our Solar System, aside from the matter that is consumed in fusion in the core of the Sun, converted to energy, and radiated out into space.

Living creatures originate from existing matter.

mass-energy is conserved in a closed system. but that's particle physics, not biology - the energies are hugely more. in chemistry and biology, you can say that matter is conserved and energy is conserved separately.

living creatures grow by eating food, as you may have noticed. no new matter involved, just rearrangment of the old matter - life, death, decay, manure-spreading, more vegetables...

the earth is not a closed system - it gets energy from the sun. although, it's in balance - it eventally emits all that energy as heat radiation. it also gets a bit of extra mass as meteorites and loses some as gas from the top of the atmosphere, but not enough to worry about

Firstly - the conversation of matter rule isn't true.

Secondly - where do you thing the matter comes from to form living creatures? It comes from matter being ingested or inhaled.

matter can be CONVERTED TO ENERGY as in explosions

a hydrogen bomb uses E = mc^2 to convert some of the mass of the hydrogen atom into energy ..

the matter is just changed from MATTER TO ENERGY ...

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when you make antimatter that is production of matter because when you use HUGE AMOUNTS OF ENERGY ..

in a cyclotron you can produce two identical particles from that energy

one is a particle of matter and one is a particle of antimatter..

the energy is LOST and the matter now takes its place ... and yes it takes 2 times the energy to produce one particle to produce the pair of particles .. this can only be done in pairs...

when the two particles then touch again which they will if left to themself they will attract each other.. because they are of opposite charge..

for example if a positron and electron are created.. then the positron has positive charge of 1.6*10^-19 coul and the electron has charge of - 1.6 * 10^-19 coul

both will be annihilated by the equation E = mc^2 and will produce a minimum of 2 photons... that must travel in opposite directions to cancel their momentum.

so again we had two mass's one matter and one antimatter both having mass... and these two mass's when destroyed produced energy equivalent to their potential energy.. of their creation..

these living creatures are just recycled material

no cuz the matter that makes you comes from your food