Answer:
12-14 october
Explanation:
The probable period of exposure is calculated as follows:
- Know the range of the incubation period
- Start counting back from the days of the first case by subtracting the first number of incubation period range
- Count back the days from the last case by subtracting the last number of incubation period range.
- This will give a range which will be the period of exposure.
From the question,
- Incubation period range 1-15
- Date of first case = october 15
- Therefore, first date of exposure = 15 -1 = 14
- Date of last case = 22
- Therefore, last date of exposure = 27 - 15 = 12
- Thus, the range is 12-14 october which is the probable period of exposure.
Answer:
Option A
Explanation:
In this case, there are two varieties of horses: Domestic horses that are raised and bred by humans and Wild horses that lives in the wild. The issue of varieties in coat colour of domestic horses can be explained as what occured by selective breeding, also known as artificial selection which is a technique by which humans develop new offsprings with desirable and suitable characteristics. These breeders select two parents that possess beneficial phenotypic traits to mate, producing offsprings with those desired traits such as strength and also for coat colour as stated.
<span> Negative staining method is used to view viruses, bacteria, bacterial flagella, biological membrane structures, lipid aggregates and proteins or protein aggregates, which all have a low electron-scattering power. This method is used to view cells or certain organelles of cells more clearly under the microscope in the field of microbiology. </span>
The carbon cycle is affected by a variety of factors, and happens through different processes. The processes can be divided into two, which are biological processes and geological processes. The biological aspect covers the use and production of carbon by living organisms. The geological aspect covers physical processes such as volcanic eruptions, and weathering of rocks, which may result to release of carbon back to the atmosphere. However, both of these aspects can be affected by recurring events in Earth's history. One is the switching between glacial and interglacial periods, and the other one is the seasonal changes. Glacial periods can lead to lower temperatures and lower carbon levels in the atmosphere. In contrast to this, warmer interglacial periods result to higher carbon levels primarily due to an abundance of life. Seasonal changes have a similar effect that can be observed at a shorter time. Human activities such as burning of fossil fuels and deforestation may also bring changes to the carbon cycle.
