Viruses cannot replicate by themselves, because they lack a lot of the cellular machinery to do so. This is why they have to invade a cell, and use the cells cellular machinery to help the virus replicate.
This is the reason they are not considered living.
Answer:
A
Explanation:
<em>The active state of cell division covers the prophase, metaphase, anaphase, and telophase. The total number of observed cells that were undergoing cell division can, thus, be calculated by adding the number of cells in each stage of the cell division.</em>
Total number of cell in division = 20+4+2+4
= 30
Probability that a randomly chose cell will be undergoing cell division = <em>number of cells in division/total number of cells</em>
= 30/200
= 0.15 or 15%
The correct option is, therefore, A.
All amino acids contain amine (-NH2), carboxyl (-COOH) and R group (side chain) with hydrogen (H).
All of the 20 amino acids coded by genetic code have N-terminus (amine) and C-terminus (carboxyl) and those are called functional groups. The key components of amino acids are hydrogen, oxygen, carbon and nitrogen. They can be classified in different subgroups according to their polarity, the core structural functional groups, side chain group type, pH.
Answer: Root
Explanation: The root system includes those parts of the plant below ground, such as the roots, tubers, and rhizomes. Plant cells are formed at meristems, and then develop into cell types which are grouped into tissues.