Robert Hooke was the first scientist to discover cell. This discovery was made possible by the use of microscope which he invented. With this microscope, Robert examined a cork and noticed pores which filled the entire volume of the thin slices of cork; he called the pores cells. This discovery was made in January 1653.
The correct answer is: Layer 1, layer 2, and layer 4 in all three regions.
The index fossils are fossils that are commonly used for identifying a geological period of time, and these fossils are also very wide spread, as well as having a rapid evolutionary trends.
By this picture, we can easily see that even though we have rock strata from different regions, the same layers contain the same fossil, and it is a fossil that also is rapidly evolving so has a minor change in each layer.
Answer:
Mechanical barriers — which include the skin , mucous membranes , and fluids such as tears and urine — physically block pathogens from entering the body. Chemical barriers — such as enzymes in sweat , saliva , and semen — kill pathogens on body surfaces.
Answer:
All results for the experimental groups involving wing surgery would be invalid.
Explanation:
The experimental group involving wing surgery would not lead to correct results because it is a direct parameter that is impaired. This has been already clearly stated in the question that these flies are prone to attack compared to those which are not treated. There could be several reasons for that such as: (1) the reattachment would not have been successful, and/or (2) the flies' health (fitness) status would have been compromised.
On the other hand, it is not correct that all experimental groups will lead to incorrect results because the untreated flies were not attacked (or less attacked). Similarly, there is no condition given for houseflies rather only zonosemata flies. So 3rd option is also not possible. Finally, the reliability of the results would definitely change because the treated flies would be more attacked and lead to a clear difference in results.
