Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period. Index fossils are useful because they tell the relative ages of the rock layers in which they occur.
Cell division happens twice during meiosis. One starting cell can produce for gametes (eggs or sperm.) In each round of division, cells go through four phases called prophase, metaphase, anaphase, and telophase.
prophase During prophase the chromosomes become visible as paired chromatids and the nuclear envelope disappears. This phase includes reduction division, which is where the number of chromosomes is decreased from 46 (diploid) to 23 (haploid.)
metaphase This is where the 23 remaining chromosomes become attached to the spindle fibers.
anaphase During this phase, the chromosomes move away from each other to one or the other pole of the spindle fiber.
telophase In which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.
interphase This is a resting period.
An organism can "make a living" and survive in its niche.
Answer:
13 is the answer for both
Explanation:
The atomic number is also the atoms count of protons and electrons when the element is of a neutral charge.
