dinosaur footprint
Explanation:
A dinosaur footprint is an example of a trace fossil. A trace fossil is a type of fossil that shows the activities of organisms that lived in the past.
- Fossils are the preserved remains of organisms that lived several years ago.
- Fossils are usually found in sedimentary rocks and thick layers of ice in temperate and polar regions.
- Body fossils are the remains of the body parts of an organism that has been preserved. They can be skeletal parts, teeth, eggs e.t.c
- A trace fossil shows the preserved remains of the activities of an organism.
- They can be fingerprints, burrows and borings, feccal pellets e.t.c
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Answer:
that's because....
group 1 (e.g Na, K) those tend to lose one electron to gain noble gas electron configuration.
they can achieve that by just losing one electron from their outer shell.
as you go down the group 1, element gets bigger in size, which means there is more space between nucleus (which is in center of atom) and electron of outer shell. the more far away they are the less attraction force between them.
so its easier for potassuim to lose one electron than for lithuim.
so that means potassium will easily give up 1 electron to react with non metal or other element therefore it is more reactive than lithuim
but in case of non metal, the opposite happens but simple to understand.
as you go down the group 7 (halogen- Cl, Br, I) element will get bigger therefore force between nucleus and outer electron is getting smaller. they have to gain 1 electron in order to fill the outer shell (to gain noble gas electron configuration.)
as florine is more smaller in size than clorine it is more reactive because florine has more tendency to pull extra electron from metal or other element towards its side. so it easily gain 1 electron to react.
Plants that have nigrogen fixing bacteria in their roots are called
legumes.
Beaker does thermometer measures the thermal energy in the air
The advantage of steam distillation over simple distillation is that the lower boiling point reduces decomposition of temperature -sensitive compounds.