Answer:
The fish did not yet exist when the old layers of rocks were deposited. In fact, animals with hard parts did not evolve until about 600 million years ago, which is only about 13% of the 4.5 billion year age of the Earth. Multicellular animals without hard parts left tracks in older sediments, but had no fossilize-able body parts.
Explanation:
Answer:
plant cells have a rigid cell wall that helps it keep shape and animal cells don't
Answer:
The species that develop in aquatic environments, need to be able to have an adequate locomotion and according to the hydrostatic pressure in the water, which this pressure has the opposite direction to gravity in terrestrial life.
Explanation:
Vertebrates that have a skeleton are accustomed to gravitational forces, and this bone structure is what allows adequate locomotion to perform movements as a function of the force of earth's gravity, in water the force of gravity has no effect, since that the hydrostatic force predominates, which the direction is opposite to the gravitational forces.
Amorphous bodies, with few solid structures, not bony, make them better adapt to movements in water masses that are promoted by hydrostatic forces.
Answer:
Nitrogen-fixing bacteria is capable pf transforming nitrogen present in the atmosphere into fixed nitrogen i.e. usable for plants.
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Answer:
The clear water representing blood, which runs through the
plastic tubes, will become green as particles from the cardboard tube
are absorbed.
Explanation:
the bold letters are answers