Answer:
a. All of these
Explanation:
<em>The characteristic of skin that makes it unpleasant for most bacteria would be due to all of the conditions.</em>
Most bacteria require humid condition in order to grow and as such, the desiccated nature of the normal human skin makes it difficult for them to establish themselves and grow on it.
The pH of the skin is usually acidic due to the production of lactic acid during sweating and the activities of the normal skin bacteria. The acidic pH hinders the growth of bacteria that can potentially become pathogenic to the skin.
Also, the skin produce antimicrobial substances at low pH which hinders the growth of pathogenic bacteria.
Hence, options b, c, and d are correct.
1. turn off the water when brushing your teeth
2. turn of the lights when leaving a room
3. turn off the lights in the morning and use sunlight coming through the windows to light the rooms
4. turn off the TV when you leave the house
Answer:
Option (e).
Explanation:
The two main types of immune cells are B-cells and T-cells. B cells are antibody producing cells where as T cells are antigen presenting cells.
A scientist claimed that a new blood borne virus can be indestructible by CD8+ cytotoxic T cells and kills many cells. But the medical community quickly denounces the warning as irrelevant because only CD8+ cells are not the only cells that are capable of removing viral infection. Natural killer cells are also involved in virus killing. The blood borne virus can not kill million cells as they are involved in the difficult mode of transmission.
Thus, the correct answer is option (E).
The second step is: Formulation of a hypothesis to explain the phenomenon in the form of a causal mechanism or a mathematical relation