Answer:
Structures that are still present but currently serve little to no purpose
Explanation:
<em>Vestigial structures/organs are general defined as structures/organs that are present but poorly developed without any functional use in the present living organisms but thought to have been fully developed and functional in their ancestors.</em>
Fully developed and functional organs gradually become less developed and non-functional across generations as the environment keeps changing and organisms found lesser use for the organs. An example includes the <u>caudal vertebrae</u> found in man which is kind of useless but thought to have been fully developed and functional in the ancestors of man - the monkeys.
<u>Vestigial organs are often used as one of the morphological evidence of the evolution of living organisms.</u>
We need options :) but stem cells are a amazing type of cells that are able to develop into many different types of cells <span>First, they are unspecialized cells capable of renewing themselves through </span>cell division<span>, sometimes after long periods of inactivity. Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions.</span>
The root word of Unicellular already tells you the answer. Uni means only one cell. So the answer is one cell.
Answer:
The answer is b. Both of them are characterized by selective permeability.
Explanation:
- Option a. states that both, the nuclear and the cell membrane have two layers. This is only true for the nuclear membrane that consists of two lipid bilayers whereas the plasma membrane only contains one layer.
- c. Only the nuclear membrane has nuclear pores that connect the two bilayers. The pores act as protein channels or passages that allow transport of materials. The cell membrane does contain channel proteins or transmembrane proteins but not protein channels.
- d. The nuclear membrane separates nuclear contents from the cytoplasm whereas the cell membrane separates cellular contents from the extracellular environment.
Answer:
because it comes from the everyday activities of many different people, such as fertilizing a lawn, using a pesticide, or constructing a road or building.
Explanation: