1. Which scientist developed the heliocentric model for the solar system?

Alina [70]

Answer: True

Explanation: I'm 1000% sure I know it's right.

Cells need carbon and hydrogen, and oxygen because they are essential to the cells survival and proper function through both animal cell systems, and plant cell systems

8 0

2 years ago

Since we started producing nuclear power in 1960, how common are large nuclear accidents (those that resulted in the major relea

zysi [14]

Very, very rare. Uranium used in power plants is typically only 3% U-235 (the explosive stuff), while bomb-grade uranium is nearly pure U-235. Simply, the concentration of U-235 in reactor-grade uranium is too small to start a chain reaction and detonate like a bomb.

3 0

2 years ago

Sign an experiment.

expeople1 [14]

The answers to the questions required for the design experiment above are :

If shark attack are related to the number of elephant seals in an area, then shark attack will increase as the number of elephant seal increases

If shark attack are unrelated to number of elephant seal in an area, then shark attack is unaffected by increase or decrease in number of elephant seal.

The Control Group : Beaches or areas where elephant seals aren't present or period of the year when there are no elephant seal at the beach.

The Experimental group : Beaches where varibale portions of elephant seals are found (area with high, medium or low).

The Dependent variable : Number of shark attacks

The Independent variable : The different number of elephant seals found.

Data to be collected include : The number and type of elephant seals found at various beaches and the number of shark attacks recorded at the various points.

John will be able to deduce if the number of elephant seals and number of shark attacks recorded corded are related.

The hypothesis of an experiment is a proposition which requires experimental testing in other to establish it's validity.

The Control Group refers to a portion of the subject which aren't given or exposed to the treatment used in an experiment.

The Experimental group are the portion of the subjects which are subjected to the treatment condition.

The Dependent variable is the measured variable is changes as the independent variables are tweaked.

Independent variable is the predictor variable, it causes a change in the output of the dependent variable.

Learn more : brainly.com/question/17528320?referrer=searchResults

5 0

2 years ago

A DNA fragment is introduced into the lacZ gene of a plasmid, which also contains an ampicillin resistance gene. What is the app

zhenek [66]

Answer: The bacteria transformed with this particular plasmid will form white colonies on the plates containing ampicillin and Xgal.

Explanation: The lacZ gene produces an enzyme called β-galactosidase which is responsible for the breakdown of lactose into glucose and galactose. The lacZ gene is one of the three genes (the other two being lacA and lacY) of the lac operon which is responsible for the transport and mechanism of lactose in E. coli and many other bacteria.

In recombinant DNA technology, when a plasmid is to be used to transform a host cell, such markers are used to help screen the transformed cells from the ones that have not taken up the plasmid. Xgal present in the plates is an artificial substrate which is hydrolyzed by

β-galactosidase into 5-bromo-4-chloro-indoxyl which will dimerize and oxidise into 5,5'-dibromo-4,4'dichloro-indigo. This is a blue pigment which will give blue color to the bacterial cells. Introducing a DNA fragment in this lacZ gene will make it non-functional so it will not be able to produce the enzyme.

Therefore, when a bacterial cell is transformed with a plasmid containing ampicillin resistance gene and a DNA fragment introduced in the lacZ gene and then grown on plates containing ampicillin and Xgal, white colored colonies will appear. The white colonies will show the bacterial cells that have successfully taken up the plasmid with the DNA fragment incorporated in the lacZ gene as this will render the gene non-functional and will not produce β-galactosidase which will breakdown Xgal to give blue colonies. Since the plates contain ampicillin, only the bacterial cells that have been successfully transformed with the plasmid ( the ones that have the DNA fragment and the ones without it) will grow as the ampicillin resistance will give them resistance against ampicillin in the plates. The bacterial cells that have not taken up the plasmid will not be resistant to ampicillin and will not form colonies on the plate.

This is called blue-white screening which is used to identify successfully transformed host cells. A picture of this is given in the attachment, taken from the following website:

https://www.mun.ca/biology/scarr/Blue_&_White_Colonies.html

8 0

3 years ago

The atomic number of carbon is six, which means that a carbon atom has six protons. Carbon has three naturally occurring isotope

weeeeeb [17]

Answer:

B and D

Explanation:

Since it says all carbon atoms have six electrons, we know that they only have six protons too. The carbon 13 and 14 means they have extra neutrons that increases their atomic mass.

7 0

2 years ago