Answer: An amoeba is a microscopic protozoan that is found in both terrestrial and aquatic environments. Amoebas are at the bottom of the food chain, providing nutrients for other living things. Humans are members of the primate family and are the most intelligent living things on Earth.
Answer:
B. So you can always see the entire object at the higher magnification
Explanation:
A microscope is used to view objects smaller than the naked or unaided eyes can see. The objective lens, in conjunction with the occular or eye lens, is used to achieve this purpose. The objective lens are of different magnifications as follows: 10X, 40X, 100X etc.
However, as the magnification increases i.e. higher objective, the object in the field of view becomes smaller and less focused. Hence, the object in the field of view must first be centered at a lower magnification/objective lens before changing to a higher one in order for the entire object to be seen at a higher magnification.
Answer:
Lipids are macromolecules that include oils, waxes, phospholipids, and steroids.
Answer:
1. Metaphase
2. Prophase
3. Telophase
4. Interphase
5. Interphase
6. Interphase
7. Anaphase
8. Interphase
9. Telophase
10. Metaphase
11. Interphase
12. Interphase
13. Interphase
14. Interphase
15. Prophase
16. Interphase
17. Metaphase
18. Anaphase
19. Interphase
20. Interphase
21. Prophase
22. Interphase
Explanation:
The cell cycle is divided into two main divisions. The Interphase ad the M phase or the Mitotic phase.
Throughout Interphase, the cell is not dividing yet, but it is preparing to divide. It synthesizes the nutrients it will need, and grows in preparation to become two cells. This is actually the phase the cell spends the longest time.
Mitotic phase is when the cell starts to divide. It is separated into:
Prophase:
In this phase the chromosomes are condensed and mitotic spindles start to form. These spindles are made up of microtubules that will help later on to split the chromosomes. The nuclear membrane disappears so that the chromosomes will be free to move.
Metaphase
This phase is marked by the alignment of the chromosomes in the middle of the cell. They line up and you will find the asters at the opposite ends of the cell, where the microtubules stem from, attaching themselves to the center of the chromosomes, which we call the kinetochore.
Anaphase
In this phase you will see that the chromosomes are separated by the spindle fibers and are pulled at opposite ends of the cell. The cell then becomes longer by the other spindle fibers that are not attached to a chromosome.
Telophase
This phase is the end phase. The two sets of chromosomes are then enclosed by new nuclear membranes forming two nuclei and other cellular structures just as the cells are about to separate completely. As the two new cells move further apart, in plant cells a cell plate forms, dividing the two cells. The movement of the two cells splitting apart is called cytokinesis and it happens just as mitosis is about to end.
Attached is a picture of the cell cycle of a plant cell.
Artificial selection is the breeding of the best species by humans. For example, the fastest horse or something like that. This means breeding with species with the traits that produce offspring with the desired traits. To do this variation is needed. Not all species are going to have the desired traits but not all are going to have the undesired traits. However, if there is no variation, all animals of the same species are either going to have the unwanted traits or the desired traits. Now, if they all have the traits that us, humans, don't want, then such a concept and process like artificial selection would not exist.