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3 years ago

Tina, an environmental scientist, is protesting the use of polychlorinated biphenyl (PCB).

1 answer:

6 0

<span>The EPA under the Toxic Substances Control Act also referred to as the TSCA are responsible for setting rules and regulations regarding polychlorinated biphenyl, PCB. Tina should reference the TSCA to help support her protest against the very toxic chemicals and compounds in PCB.</span>

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2 years ago

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Xylem tissue that should help you out

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2 years ago

In 1985 a biologist counted 750 pine trees in a 250 hectare forest. Using similar counting techniques, the biologist counted 1,2

Alisiya [41]

Answer:

Suppose that we have a given function f(x)

The average rate of change of the function between two values x₁ and x₂ is given by:

$r = \frac{f(x_2) - f(x_1)}{x_2 - x_1}$

a) We want to find the average (rate) of change on the size of population from 1985 to 1995.

We have that:

f(1985) = 750

f(1995) = 1500

Then we have:

$r = \frac{1500 - 750}{1995 - 1985} = 750/10 = 75$

This means that the population of trees increases, in average, at a rate of 75 trees per year.

b) What is the density of trees each year that they were counted?

This will be equal to the quotient between the number of trees and the area.

1985: number of trees = 750 pines

area = 250 ha

Then the density is:

D(1985) = (750 pines)/(250 ha) = 3 pines/ha

So 1985, there were 3 pines per hectare.

1990: number of trees = 1250 pines

area = 250 ha

Then the density is:

D(1990) = (1250 pines)/(250 ha) = 5 pines/ha

1995: number of trees = 1500 pines

area = 250 ha

The density is:

D(1995) = (1500 pines)/(250 ha) = 6 pines/ha

3) now we want to get the average change between 1985 and 1995 in the density, this will be:

$r = \frac{D(1995) - D(1885)}{1995 - 1985} = \frac{6 pines/ha - 3pines/ha}{10} = 0.3 pines/ha$

So, on average, each year the number of pines per hectare increases by 0.3

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2 years ago

13)

Julli [10]

Multiply 5730 years by 2 since two half-lives have gone by for carbon.

<u>Explanation</u>:

The half-life of a radioactive isotope depicts the measure of time that it takes half of the isotope in an example decay. On account of radiocarbon dating, the half-existence of carbon 14 is 5,730 years

The half-life of carbon-14 is 5730 years.

In this manner, after

1 half-life there is 50 % = 1/2 of the first amount left.

2 half-lives there is 25 % = 1/4 of the first amount left.

25% is two half-lives.

Every 50% of life requires 5730 years.

So two half-lives require 2 × 5730

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3 years ago

Can someone please help me

Usimov [2.4K]

Answer:

1A - Respiratory = trachea, lungs... however both arteries and veins move oxygen around the body, and are therefore valid answers

1B - Skeletal = bones

1C - Muscular = muscles

1D - Digestive = stomach, large/small intestine

1E - Circulatory = heart, veins and arteries

2. Cellular respiration is the conversion of sugar into energy the cell uses to function via various chemical reactions. Digestion is an example of this. Stomach acid breaks down food into sugars that cells break down further into energy to keep you alive

3. Bones contain bone marrow deep inside of them which is responsible for the creation of red blood cells. Your lungs can move air all they want but would be useless without red blood cells to take the oxygen to cells and take the CO2 away from them.

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2 years ago