Answer:
Which of the following is an advantage of an in vitro experiment?
Variables and environmental conditions are controlled.
Explanation:
An advantage of in-vitro experiment is that the variables and environmental conditions are controlled because in-vitro experiment is performed outside a living organism with the environment in control
Answer:
3. the absence of a cell wall in human cells
Explanation:
Animal cells do not have cell walls. Cell membranes separate the cytoplasm of the animal cells from the surroundings and maintain their interior. Plant cells have cellulosic cell walls. A cell wall surrounds the cell membrane of a plant cell. Cell walls serve to provide structural support and protect plant cells from pathogens. Cell walls also help keep excess water out of cells so they do not burst. Therefore, human cheek cells would not have cell walls while the onion cells would have cell walls made up of cellulose.
<span>Lymph nodes are abundant organs comprising a major part of the lymphatic system, and can indeed be found throughout the body, connected by the lymphatic vessels. However, the highest concentration of clustering occurs within in the inguinal region, cervical region, and axillary region.</span>
<h2>Cell Cycle
</h2>
Explanation:
Eukaryotes grow and divide by cell cycle.
The main parts of a cell cycle are an ordered series of events – Gap 1 or G1 phase, Synthesis or S phase, Gap 2 or G2 phase, and the mitosis or M phases.
Interphase period (G1, S, G2 phases) - cell grows by size, duplicates its content, replicates its DNA, and finally prepares for mitotic cell division
.
Mitosis and cytokinesis - formation of two identical daughter cells
Cell cycle is regulated by regulatory or restrictive checkpoints in the cell cycle which are activated with detection of a defective DNA.
Proliferation of undesired or cells with defective DNA like in case of tumor cells is controlled by the action of suppressing agents like p53 and cyclins.
The tumor suppressor gene protein p53 prohibits division of tumor cells. Cyclins regulate cell cycle by activation of the enzyme cyclin-dependent kinase.
It’s true, there are more insects than there are any other specie and more kinds
