The lac repressor prevents the lac genes in the DNA of E. coli from being expressed most of the time. The answer to your question is A. I hope this is the answer that you are looking for and it comes to your help.
Answer:
- False
- True
- True
- False
- False
- True
Explanation:
A hypothesis is a supposition draw from data to carry an investigation or an argumentation.
1. The onion cells I looked at have a nucleus. False, even though the statement is true, is not a hypothesis because is not a supposition, it is rather an observation.
2. All onion cells have a nucleus. True, it is s a <u>valid hypothesis</u> because after the observation of 10 cells you draw a conclusion or supposition and affirm that all onion cells have a nucleus.
3. All cells have a nucleus. True, it is a<u> valid hypothesis</u> it contains a supposition derived from data observation
4. Some cells have a nucleus. False, the hypothesis is not valid because all of the observed cells contained nucleus not only some of them.
5. Only onion cells have a nucleus. False, after the observation of the different type of cells you see that they all had nucleus.
6. If I look at 10 skin cells from my hand, each one will have a nucleus. True, after the observation of different cells you can infer that if you look at your skin cells, they will have a nucleus.
Answer: Yes
Explanation: Inertia: tendency of an object to resist changes in its velocity
Question 1:
<u>Answer</u>:
The "first line of defence" in innate immunity is "Physical and chemical barriers".
<u>Explanation</u>
"Physical and chemical barriers" is first line of defence includes that are ready to defend the living organism's body from infection at any time . These barriers include your skin, cilia, tears, urine flow, mucus, stomach acid, friendly bacteria and white blood cells . Skin acts as a mechanical barrier as it does not allows all the organism to pass through it unless the skin is cut or open. Similarly mouth eyes, and nose are also the ways through with the disease causing organism can enter the body. The micro-organisms that entered through these pathways are trapped either in saliva or mucus and swallowed and later either killed in the stomach or flushed out via the urine. If this first line of defence is broken or damaged, the second line of defence inside our body will be activated.
Question 2:
<u>Answer:</u>
Histamine kinins, and interleukins are examples of inflammatory mediators.
<u>Explanation</u>:
Inflammatory mediators are identified in inflammatory bowel disease IBD.These mediators play an vital role in the clinical and pathologic characteristics of the disorders. Cytokines, that are released by macrophages in due to antigenic stimuli, are binded different receptors and produce endocrine, autocrine and paracrine effects. Interleukins are a subset of a large group of 'cellular messenger molecules' called cytokines that modulates the cellular behaviour. Interleukins are not stored within cells like cytokines but they are released immediately, in response to a stimulus. Once an interleukin has been secreted, it moves to the target cell and binds to it through a receptor molecule on the surface of the cell . This interaction triggers a sequence of signals in the target cell that ultimately leads to the alteration in the behaviour of the cell.
Explanation:
scientists have found that a virus can stimulate photosynthesis in bacterial host, so im guessing yes.
