1. How many zebra mussels were there in the Hudson River within a year of their first appearance? A. 500 billion B. 500 million C. 500 thousand D. 500
2. This text explains a cause-and-effect pattern in the Hudson River ecosystem that began with the zebra mussel invasion. What effect did the zebra mussels have on the phytoplankton in the Hudson River? A. The number of phytoplankton in the river rose by a little. B. The number of phytoplankton in the river fell by a little. C. The number of phytoplankton in the river rose by a lot. D. The number of phytoplankton in the river fell by a lot.
3. Phytoplankton are one of the most important parts of the food web in the Hudson River. What evidence supports this conclusion? A. The population of phytoplankton dropped sharply soon after zebra mussels invaded the river. B. The decrease in phytoplankton caused a decrease in the river's zooplankton, fish, and native mussel populations. C. The decrease in phytoplankton meant that the river's turbidity, or cloudiness, decreased. D. Zebra mussels caused oxygen levels in the river to drop, partly by removing the phytoplankton that produce oxygen.
4. Which population was helped by the invasion of the zebra mussels? A. phytoplankton B. zooplankton C. water celery D. native mussels
5. What is the main idea of this text? A. In the years right after the invasion, zebra mussels evolved and adapted to the Hudson River ecosystem. B. In the years right after the invasion, zebra mussels caused a number of changes in the Hudson River ecosystem and food web. C. In the years right after the invasion, zebra mussels did not have a major impact on the Hudson River ecosystem or food web. D. At first, zebra mussels did not have any impact on the Hudson River ecosystem, but their impact increased over time.
6. Read these sentences from the text. "In the years right after the invasion, phytoplankton fell by 80 percent. Zooplankton (which eat phytoplankton) declined by half. And the smallest zooplankton (called microzooplankton), fell by about 90 percent." Based on these sentences, what does the word "decline" most nearly mean? A. to drop in number B. to fall over C. to increase D. to stay the same
7. Choose the answer that best completes the sentence. With far less phytoplankton, the water got clearer. ______, rooted aquatic plants such as water celery increased by up to 40 percent. A. In contrast B. However C. As a result D. Similarly
8. What are two populations that decreased as an immediate result of the zebra mussel invasion?
9. One direct effect of the zebra mussel invasion was a decrease in the cloudiness of the water. How did this affect species in the Hudson River ecosystem?
10. Once scientists understood the short-term impact of the zebra mussel invasion, they started to wonder about the invasion's long-term impact on the ecosystem. Why might the Hudson River ecosystem look different many years after the zebra mussel invasion than it did just a few years after the invasion? Use evidence from the text to support your answer.
Answer:
A) 500 billion
Explanation:
Answer: 500 billion
Zebra mussels first appeared in the Hudson River in May 1991. Within a year, scientists estimated their numbers had reached 500 billion, an enormous amount! In fact, if you had a huge balance and put zebra mussels on one side, they would outweigh all the other consumers in the ecosystem.
Explanation: Answer A.
A piece of metal has a mass of 147.8g. When dropped into a graduated cylinder, the metal displaces 18.5ml of water. What is the density of the metal?
Answer:
The answer is 7.99 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass of metal = 147.8 g
volume = 18.5 mL
It's density is
[tex]density = \frac{147.8}{18.5} \\ = 7.9891891...[/tex]
We have the final answer as
7.99 g/mLHope this helps you
Question 3
Which is the simplest form of a crystalline solid?
Answer:
metals is the simplest form of crystalline solid
Select the correct answer.
Which sentence is a scientific statement?
A.
Long hair looks better than short hair.
B.
Brick structures insulate better than wooden structures.
C.
Milkshakes should always be sweetened with honey.
D.
There is a large, apelike creature living in the Himalayas.
Answer:
B
Explanation:
Most of these are opinions. the reason that it is not d is because it is not something that can be scientifically proven. b can be proven by facts. hope this helps!
what are two partsof an atom?
Answer:
The two main parts of atom is consist of Nucleus and Electrons where in Nucleus has a positive charge while electrons have negative charge.
Which of the following is an example of a producer?
O a plant
O a bird
O a deep-sea vent
Answer:
i believe the answer is a plant
Explanation:
they provide food (energy) for those further up the food chain
Calculate the number of C atoms in 11g of carbon dioxide
Answer:
1.51× 10²³ C atoms
Explanation:
Given data:
Mass of CO₂ = 11 g
Number of atoms in 11 g of CO₂ = ?
Solution:
First of all we will calculate the number of moles of CO₂ .
Number of moles = mass/ molar mass
Number of moles = 11 g/ 44 g/mol
Number of moles = 0.25 mol
One mole of CO₂ contain 1 mole of C atom.
0.25 mole of CO₂ contain 0.25 moles of C atom.
The number of C atoms in 0.25 moles will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number .
11 g of CO₂ = 0.25 moles of C = 0.25 × 6.022 × 10²³ C atoms
1.51× 10²³ C atoms
How many atoms of sodium are in 3.80 mol of sodium, Na?
Answer:
2.29 × 10²⁴ atoms Na
Explanation:
Step 1: Define
Avagadro's Number: 6.02 × 10²³ atoms, molecules, formula units, etc.
Step 2: Stoichiometry
[tex]3.80 \hspace{3} mol \hspace{3} Na(\frac{6.02(10)^{23} \hspace{3} atoms \hspace{3} Na}{1 \hspace{3} mol \hspace{3} Na} )[/tex] = 2.2876 × 10²⁴ atoms Na
Step 3: Simplify
We have 3 sig figs.
2.2876 × 10²⁴ atoms Na ≈ 2.29 × 10²⁴ atoms Na
what is the maximum number of vacant electrons an element can have (correct answer gets brainliest)
a.6
b. 18
c. 10
d.8
Answer:
I think 10 or 18
Explanation:
Which is the variable that you are measuring and observing for?
O Dependant Variable
Independant Variable
Constant
O Exponent
Answer:
Dependent variable
Explanation:
its what you measure
It took 3 hours for a train to travel the distance between two cities at a
velocity of 290 miles/hour. What is the DISTANCE between the two cities?
Pls hurry!
Answer:
The answer is 870 milesExplanation:
The distance covered by an object given it's velocity and time taken can be found by using the formula
distance = velocity × timeFrom the question
velocity = 290 miles/hour
time = 3 hours
The distance between the two cities is
distance = 290 × 3
We have the final answer as
870 milesHope this helps you
when moving down a column in the periodic table, which of the following increases
A. atomic mass
B. atomic number
C. group number
D. atomic mass and atomic number
Answer:
D.) atomic mass and atomic number
What is the volume of a rock that has a mass of 50 grams and a density of
5 g/ml?
Explanation:
density = mass/ volume
so,
volume = mass/ density
volume = 50 g/ 5 g/ml³
volume = 10 ml³
How are heterogeneous and homogeneous mixtures separated?
Answer:
Explanation:
In heterogeneous mixtures, two or more ingredients (or phases, regions with uniform composition and properties) intermingle, but remain physically separate. Often it is possible to separate the original ingredients by physical means, such as filtering.
Find molar mass of gold
Answer:
196.96657 g/m
Explanation:
The molar mass of gold is 196.96657 g/m
(I don't know if there is a picture or not to this but that is the molar mass of gold.)
what did we discover with the following experiment
a d d m y s n a p gianavaughn007 ;)
Select the correct answer.
Andy is waiting at the signal. As soon as the light turns green, he accelerates his car at a uniform rate of 8.00 meters/second2. What is the displacement of Andy’s car after 30.0 seconds?
A.
1200 meters
B.
2400 meters
C.
3600 meters
D.
4800 meters
E.
7200 meters
Answer:
3600
Explanation:
A Boron atom has 5 protons, 6 neutrons, 2 electrons, and a mass of 11. Select 2 that apply.
a
+ 2 charge
b
+ 3 charge
c
electrons were lost
d
electrons were gained
e
zero charge
Answer:
B and C
Explanation:
Despite the superior intellect of our lab workers, none of the problems above actually caused the discrepancies. This occurs sometimes with unexpected or unexplained results, where multiple hypotheses can explain the cause of the discrepancy occur. Here is a challenge: closely examine each video, and see if you are more observant than our lab workers by determining the actual source of the error.
Answer:
Haven't evaporated all of the water
Explanation:
One of the main sources of error that occur in a formula of a hydrate lab is that all of the water is not evaporated. We can see at the end of the video that half of the CoCl2 is a light blue colors and the other half is a dark blue color. This indicates that all of the water still has not been evaporated off, resulting in the actual mass of the salt to be greater than the predicted value.
Please help brainiest
in acidic medium dichromate Ion oxidized ferrous sulphate to ferric sulphate and and it self reduced to chromium 3 + ions write a balanced equation to represent this this redox reaction use Ion electron method
Answer:
Cr
2
O
7
2−
+14H
+
+6Fe
2+
→2Cr
3+
+6Fe
3+
+7H
2
O
During the reaction, the oxidation number of Cr decreases from +6 to +3. Net decrease in the oxidation number of one Cr atom is 6−3=3. For 2 Cr atoms (in dichromate ion), the total decrease in the oxidation number is 2×3=6
The gram equivalent weight =
Total change in the oxidation number
gram molecular weight
=
6
294
=49
common element in all the organic compound another than hydrogen is
Answer:
Although all organic compounds contain carbon, and almost all have hydrogen, most of them contain other elements as well. The most common other elements in organic compounds are oxygen, nitrogen, sulfur, and the halogens.
Explanation:
I hope this helped!
I Need Help With This I’m so Confused on it.
Answer:
i need help wit dat twoExplanation:
yeah........
Which option is an example of a physical property?
reactivity
flammability
toxicity
solubility
Answer:
Solubility
Explanation:
Solubility is the only thing that you can hold in your hands and touch (you can't hold reactivity or flammability). Physical = you can touch and hold it
Which of the following ways can the volume of a gas be changed, without changing its mass? Select all that apply.
It can be compressed into a smaller container.
It can be spread out into a larger container
It can be dissolved into a liquid.
It can increase the number of particles
It can be heated up.
Answer:
It can be spread into a smaller container
It can ve spread out into a larger container
It can be dissolved into a liquid
Answer:
the answers are
It can be compressed into a smaller container.
It can be spread out into a larger container.
It can be dissolved into a liquid.
It can be heated up.
Explanation: I just did the assignment and these were the correct answers
Calculate the number of atoms in a 1.05 x 10^3 mole sample of argon.
Answer:
6.32*10²⁶ atoms
Explanation:
Use Avogadro's Number to convert to atoms.
[tex]1.05*10^3 mol Ar * \frac{6.022*10^23 atoms}{1 mol Ar}[/tex]
Valerie wants to examine the properties of a thick liquid but is finding it difficult to pour the liquid into a beaker. She needs to finish her investigation before the end of class. Which method will allow her to pour the liquid easily?
boiling the liquid vigorously
applying heat to the liquid
placing the liquid in the refrigerator
mixing the liquid with another solution
Answer:
B. applying heat to the liquid
Explanation:
Edge2020
Have a great day y'all :)
Applying heat to the liquid allows Valerie to pour the liquid easily, hence option B is correct.
How does heat causes melting of thick liquid?A physical process called melting or fusing causes a substance to change its phase from a solid to a liquid.
This happens when the solid's internal energy rises, usually as a result of heat or pressure being applied, which raises the substance's temperature to the melting point.
A solid's particles generate enough energy during heating to overcome the strong bonding forces holding them tightly together.
When the mobility of the molecules in a solid accelerates to a point where it outweighs the attraction between the molecules, melting takes place.
Therefore, by applying heat to the liquid allows her to pour the liquid easily, hence option B is correct.
Learn more about plate melting, here:
https://brainly.com/question/11331049
#SPJ7
When a candle is lit and allowed to burn for 15 minutes, some wax drips and collects at the base of the candle, and the candle becomes shorter.
Why did the candle become shorter? What happened to the missing section of the candle?
Answer:
The missing section of the candle burns away and evaporates while some drips and collects at the base.
Explanation:
This is because a chemical reaction is occurring due to the heat, causing the molecule in the candles wax to move around faster and faster therefore causing melting.
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