When stem cells grown on hard, rigid surface, then they became bone cells. Researchers demonstrate in Nature materials that human mesenchymal stem cells grown on a rigid substrate for some time become biased toward differentiating into bone-cell lineage, whereas cell grown on softer surfaces are just likely to eventually follow a bone or fat cell fate.
1.Tyrannosaurus Rex Lived in the Mesozoic Era
2.The largest mass extinction happened in the Paleozoic Era
3.Life exploded for the first time in the Precambrian Era
4.The Chicxulub crater in the Cenozoic Era
Answer:
The nucleus, cell membrane and cytoplasm.
Explanation:
The nucleus, cell membrane and cytoplasm are three elements that cannot be absent in a cell because they are necessary for the survival of the cell. The nucleus controls and regulates the activities happening inside the cell e.g. growth and metabolism etc. Cell membrane acts as a wall to protect the inner part of the cell from the external environment as well as allows nutrients and gases inside and outside the cell. Cytoplasm serves as a medium for the conduction of nutrients and waste from on place to another and also for the medium for organelles in which they floats.
The correct option is (a) 2 → 4 → 1 → 3
A change occurs in the environment. → Poorly adapted individuals have decreased survivorship. → Well-adapted individuals leave more offspring than do poorly adapted individuals. → Genetic frequencies within the population change.
<h3>
What is genetic variation in population?</h3>
- The presence of various alleles, or different gene versions, within a population indicates genetic variety.
- If there is genetic variation, then everybody in the population will have various genotypes depending on the alleles they carry.
- Genetic loci that have many alleles are said to be polymorphic. Human characteristics like blood type and eye color, for instance, are polymorphic.
Learn more about the genetic variation with the help of the given link:
brainly.com/question/848479
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