Let workdone 1 boy in 1 day be b

and that of 1 girl be g

From the given data,

4(5b + 3g) = 23

20b + 12g = 23 .......(a)

2(3b + 2g) = 7

6b + 4g = 7 ........(b)

Solving (a) & (b), we get

b = 1, g = 1/4

Let number og girls required be 'p'

6(7 x 1 + p x 1/4) = 45

=> p = 2.

Hence, number of girls required = 2

The three statements make up the cell theory are::

1. All living things are made up of cells.

2. Cells are the basic unit of structure/function in living things.

3. New cells come frome exisiting cells.

These cells can vary widely, but all living things are composed of cells.

The given number series is 96, 95, 87, 78, ? 

It follows a pattern that,

$$\begin{gathered} 96 \\ 96 - 12 = 95 \\ 95 - 23 = 95 - 8 = 87 \\ 87 - 32 = 87 - 9 = 78 \\ 78 - 43 = 78 - 64 = 14 \end{gathered}$$

Hence, the next number in the given number series is 14.

ELA - English Language Arts.

The major greenhouse gases (GHG’s) solely responsible for greenhouse effect are Carbon dioxide, Ozone, Methane and Water vapor. Although these gases comprise 1% of our atmosphere, they act like a thick warm blanket outside that surrounds this planet and regulate climate control. Greenhouse effect is not bad. In fact, it is needed for all of us to survive on planet Earth. In short, the greenhouse effect is nothing but a naturally occurring process designed by nature that aids in heating earth’s surface and helps to maintain ecological balance.

Now, while some of that heat dissipates into space, some of it burns along the atmosphere, and some of it penetrates the atmosphere and finds its way into the lower atmosphere and the planet’s surface. This in turn raises the average temperature of the Earth. Therefore, the increase in the Earth’s surface temperature due to increase in the number of greenhouse gases leads to global warming.

Causes of Green House Effects ::

* Burning of Fossil Fuels

* Deforestation 

* Increase in Population

* Farming

* Industrial Waste and Landfills.

Geothermal power plants are used in order to generate electricity by the use of geothermal energy (the Earth's internal thermal energy). They essentially work the same as a coal or nuclear power plant, the main difference being the heat source.

Geothermal power plants use hydrothermal resources that have both water (hydro) and heat (thermal). Geothermal power plants require high-temperature (300°F to 700°F) hydrothermal resources that come from either dry steam wells or from hot water wells.

Romans (753 BC - AD 410) began public health and sanitation systems.

Romans established the first public health and sanitation systems by building sewers and aqueducts.

They also treated diseases with diet, exercise and meditation.