Which of the following represents an upside-down image? o a. +doo b. -doo c. +mo d.-m

D. -m

Explanation:

The magnification of an image is equal to the following ratio:

where

y' is the size of the image

y is the size of the real object

We have two situations:

- When m is positive, it means that y' has the same sign of y --> so the image has same orientation of the object (= image is upright)

- When m is negative, it means that y' has opposite sign to y --> so the image has opposite orientation to the object (= image is upside down)

So, the correct answer that describes an upside-down image is

D. -m

i need with 1.3.2 investigate cycling o2 and co2 apex

we need to see it

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =