Answer:
Evolution in nature by natural selection only modifies the structures present in the ancestors and favors the better adapted structures.
Explanation:
An engineer can design the bones and muscles of the forelimbs of given organisms as per their needs and give rise to new unique structures for each of these organisms.
On the other hand, evolution in nature allows the modification of existing traits by the accumulation of variations. The adaptive variations in the traits are then favored by natural selection. Therefore, forelimbs of mammals such as horses, whales, and bats have evolved by modification of the forelimbs present in their common ancestors.
The limitation of modification of existing structures does not allow the formation of a completely new structure.
Meory T cells are defined as a subset of infection including cancer-fighting T cells
Answer:
I only know 2 of the main ones.
1. Moving
2. Eating
Explanation:
If I figure out the other 2 I will let u know.
<span>The amount of genes we have is considered an estimation. They
used to believe it was around or above 100,000. Then when the human genome project (HGP)
was completed in 2003 their estimation brought it down to 20,000 to 25,000. You
can find their current work at “national human genome research institute” and
also a free public database. </span>
Answer:
Cheek cells lack a rigid cell wall and due to this their shape is not as well defined as a plant cell.
Explanation:
- Cell wall is the outermost structure in plant and bacterial cells.
- The plant cell wall is made up of cellulose and provide rigidity and shape to the cell.
- In animal cell, the cell wall is absent and the outermost part of the cell is the cell memrane.
- This is the reason that most animal cell lack rigidity and shape.