The answer is A, Sound waves must have materials to bump together to transfer the waves.
Kidneys couldn’t work without the liver because water wouldn’t leave the body.
Hope this helps!
~Brooke❤️
Answer:
The factors which remained constant are as follows -
- material used as the membrane
- amount of substances used
- number of trials
The factors which have shown variation are as follows -
- molecule size (large starch molecules vs. small glucose molecules)
- whether the molecules diffused through the membrane (tubing)
Explanation
Some factors with in the experiments remained constant from the point of starting of the experiment to its end. While some factors were varied to study its impact on the experiment rate of progression or on the final product formed. Thus , out of the following given factors, the ones that remained constant are -
- material used as the membrane
- amount of substances used
- number of trials
The factors which have shown variation are as follows -
- molecule size (large starch molecules vs. small glucose molecules)
- whether the molecules diffused through the membrane (tubing)
There are some reasons which could be mentioned:
1)Energy is lost as heat at each feeding level
2)Consumers who feed directly on plants have more energy for themselves than consumers feeding on other consumers. Indeed, energy again is lost in each level.
3)Feeding cattle is not productive, because energy must be transferred from plants to the cattle and then to people.
