During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever ≥ 39°C lasting >2 days with three or more symptoms (i. e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years. The portal of entry for the pathogen was:.a. gastrointestinalb. skinc. respiratoryd. urinary

Respiratory

Explanation:

The mode of transmission of the disease is through respiratory system because it spread due to the presence of the microbes in air.

As the wind blew from northwest to other side, the pathogens were carried from one place to another along with the blowing wind.

The pathogens entered into the body by the nasal passage when the sheep inhaled the air. The pathogens entered into the body of the sheep and cause pneumonia into them. which resulted in chills, sweat, fever, fatigue et cetera.

Hence, the portal for the entry of the pathogens is the respiratory track of the sheep.

answer: zinc is the substance which has a volume of 1.38 .

density is defined as the mass of an object per unit volume.

it can be calculated by dividing mass of a substance by its volume i.e.

si unit of density is kg per cubic meter and cgs unit of the same is gram per cubic centimeter.

now from the given data volume can be calculated by the formula .

hence, the volume of aluminium will be = which comes out to be 1.703 .

similarly, volume of zinc, chromium, and nickel will be 1.378 , 0.869 , and 0.356 respectively.