Suppose a scientist wants to test the effects of a pesticide on mice, so he tags nearby families of wild mice. In each nest, he assigns some mice to the control group and some to the test group. He takes pictures of the mice and measures them. Then, he gives small doses of the pesticides to the mice in the test group. He returns regularly to make observations. What is a probable source of error for this experimental design? A. The scientist could not control the dose given to the wild mice. B. The scientist's results were biased by his expectations. C. The scientist could not control the environment of the wild mice. D. The scientist did not use a control group in the experiment.

QUESTION POSTED AT 18/01/2020 - 06:51 AM

Related questions

Dichotomous keys ask A.open-ended questions about animal behavior. B.open-ended questions about easily observable characteristics. C.yes-or-no questions about animal behavior. D.yes-or-no questions about easily observable characteristics.

The right option is; D.yes-or-no questions about easily observable characteristics.

A dichotomous key is a tool designed by scientists to help its users to identify a particular type of object and organisms based on physical characteristics. A dichotomous key is divided into two sections and it usually contains specific questions with two choices (yes or no) in each step. When a question is answered, the key guides the user to the next question to ask until the user is able to correctly identify the name of the unknown organism.

ANSWERED AT 24/02/2020 - 12:37 AM


QUESTION POSTED AT 24/02/2020 - 12:37 AM

Eugene describes the physical property of a material as “sweet and floral.” What physical property of the material is Eugene most likely observing? boiling point shape hardness odor

I believe the correct answer is "D.) odor"
Hope this helped, please let me know if I was correct.

ANSWERED AT 24/02/2020 - 12:32 AM


QUESTION POSTED AT 24/02/2020 - 12:32 AM

In pea plants, yellow (Y) seed color is a dominant trait, and green seed color (y) is a recessive trait. Which resulting plant with yellow seeds could produce a plant with green seeds in the next generation? A. YY B. Yy C. yy D. Yg

Answer: The correct answer is-

B. Yy

As per the information in the question,  yellow (depicted by Y allele) seed color is a dominant trait whereas green seed color is a recessive trait ( depicted by y allele).

A dominant trait always masks the expression of a recessive trait.

Presence of single dominant allele ( such as in Yy, which shows heterozygous dominant genotype) in the genotype can produce a dominant trait whereas recessive trait is only expressed when its genotype is homozygous recessive (such as yy that is both alleles should be recessive allele) .

A plant with genotype Yy will form two gametes that is Y and y.

When such plants are allowed to interbreed, there is a probability of 25% of producing green seeds in the next generation.

Refer punett square.

ANSWERED AT 24/02/2020 - 12:32 AM


QUESTION POSTED AT 24/02/2020 - 12:32 AM

Letter D is the part of the cell that makes proteins. What is letter D? A) ribosomes B) chromosomes C) chloroplast

the answer is A.RIBOSOMES

ANSWERED AT 24/02/2020 - 12:27 AM


QUESTION POSTED AT 24/02/2020 - 12:27 AM

What is a trait that has probably been selectively bred for by human beings?

Selectively bred fro humans or animals?
If for humans, less body hair.. I guess.. im not sure
If for animals: Cows create more milk due to genetic mutation

ANSWERED AT 23/02/2020 - 11:59 PM


QUESTION POSTED AT 23/02/2020 - 11:59 PM

What do error bars show within treatments?


Error bars within treatments illustrate confidence intervals, standard errors, standard deviations or other quantities. However, different types of error bars exist, so figure legends must be sure to distinguish which error bar is being represented. 

ANSWERED AT 23/02/2020 - 11:57 PM


QUESTION POSTED AT 23/02/2020 - 11:57 PM

Most streams result from what

Answer:

A stream refers to a water body with the surface water flowing within the banks and bed of a channel. The stream generally results due to the majority of the water coming from snow and rain. The majority of this water gets entered into the atmosphere again by the process of evaporation from water bodies and soil, or by plant’s evapotranspiration. Some of the water continues to sink into the Earth by infiltration and turns into groundwater, the majority of which ultimately goes into the streams.

ANSWERED AT 23/02/2020 - 11:56 PM


QUESTION POSTED AT 23/02/2020 - 11:56 PM

Why did the invention of pcr make dna fingerprinting possible

Answer:

With the invention of the PCR technique , DNA profiling took huge strides forward in both discriminating power and the ability to recover information from very small or degraded starting samples.

The process of PCR mimics the biological process of DNA replication but confines it to specific DNA sequences of interest.

In PCR process , the DNA sample is denatured into separate individual polynucleotide strands through heating. Two oligonucleotide DNA primers are used to hybridise to two corresponding nearby sites on opposite DNA strands. Thus two new copies of the sequences of interest are generated.

Repeated denaturation , hybridisation and extension in this fashion produce an exponentially growing number of copies of the DNA of interest.

Quantitative PCR methods enable automated , precise and high - throughput measurements.

ANSWERED AT 23/02/2020 - 11:50 PM


QUESTION POSTED AT 23/02/2020 - 11:50 PM

If Garrett counts the number of waves that reach the shore over a 10 second period, what property of the waves is he measuring?

Answer: frequency

Explanation:

ANSWERED AT 23/02/2020 - 11:38 PM


QUESTION POSTED AT 23/02/2020 - 11:38 PM

Humans cannot digest food without the aid of small single-celled organisms that live in our digestive tract. These small organisms help humans digest food by breaking down complex food molecules. Which common name is associated with these single-celled organisms that help humans digest food? A) algae B) bacteria C) protozoa D) virus

Bacteria are single-celled organisms that help humans digest food.

Explanation:

The symbiotic association of bacteria and human is of importance in the process of digestion. These bacterias are found in our gut, large intestine and sometimes in small intestine also. These bacteria break down big molecules into useful forms. Bacteria are also responsible for producing vitamin k2 and vitamin B in large intestine. They also help in mobilising of xenobiotics, bile and sterols.

ANSWERED AT 23/02/2020 - 11:32 PM


QUESTION POSTED AT 23/02/2020 - 11:32 PM

What type of information is being presented by a scientist who has a reason for presenting information a certain way?

You cant answer this without looking at the diagram. sorry.

ANSWERED AT 23/02/2020 - 11:30 PM


QUESTION POSTED AT 23/02/2020 - 11:30 PM

Grain products are a good source of carbohydrates and . a. Vitamin B complex b. Vitamin A c.Calcium

Answer:

Grain products are a good source of carbohydrates and Vitamin B complex

Explanation:

ANSWERED AT 23/02/2020 - 11:28 PM


QUESTION POSTED AT 23/02/2020 - 11:28 PM

18. In a species of wild animal, claw size is determined by a combination of two alleles. Allele Q codes for large claws, while allele q codes for small claws. Individuals with a heterozygous genotype possess claws of medium size. Members of the species depend on their claws to be able to burrow in the ground and find food. But in an area where the ground has always been soft, gradual climate change has caused the dirt to become hard and compact. Which statement best predicts the change that will occur in the affected populations? A. Allele q will decrease in frequency. B. Allele q will become dominant to allele Q. C. Allele Q will become dominant to allele q. D. Allele Q will decrease in frequency.

Answer: The correct answer is- A) Allele q will decrease in frequency.

According to the information in the question, allele Q codes for large claws and allele q codes for small claws in a species of wild animal.

This indicates that larger claws will enable the wild animals to burrow more in the ground and find their food. As the change in the climatic conditions caused the dirt on the ground to become hard and compact.

This will result in change in the frequency of allele of the population as allele Q will increase because larger claws will provide more advantage (in context of burrowing) to the animals for getting their food, whereas frequency of q allele will decrease ( as smaller size of claws will not be that beneficial to them in hard and compact ground).

Thus, option A) is the right answer.

ANSWERED AT 23/02/2020 - 11:24 PM


QUESTION POSTED AT 23/02/2020 - 11:24 PM

Mario at lab table A needs a pair of forceps (tweezers). Max at lab table B tosses Mario a pair. In terms of laboratory safety, which best describes Max’s behavior? a. It demonstrates a lack of planning. b.It is unsafe and can result in someone getting hurt c.It is safe and appropriate d.It shows proper handling of equipment

Answer: Option (b) is the correct answer.

Explanation:

When Max tossed a pair of forceps (tweezers) from his table towards Mario's table then it is possible that forceps might hit someone and that person will get hurt.

Hence, it is not a proper way or method to handle equipment in the laboratory.

Thus, we can conclude that in terms of laboratory safety, it is unsafe and can result in someone getting hurt.

ANSWERED AT 23/02/2020 - 11:14 PM


QUESTION POSTED AT 23/02/2020 - 11:14 PM

Which major change can occur in a small population that is the result of the genetic drift? A. recessive traits always become dominant B. new individuals add their genes to the gene pool C. large changes in allele frequencies can occur in a short time.

The answer is C. large changes in allele frequencies can occur in a short time.

Genetic drift is a change in the frequency of alleles in a population as a result of random sampling of organisms and it decreases genetic variation of the population. In specific circumstances, large and rapid changes in allele frequencies can occur in a short time. The smaller the population, the more susceptible it is to genetic drift.

ANSWERED AT 23/02/2020 - 11:09 PM


QUESTION POSTED AT 23/02/2020 - 11:09 PM

Which of these is an environmental effect of burning fossil fuels? A) Soil erosion B) Temperature increase C) Habitat succession D) Flooding

I believe that would be a temperature increase

ANSWERED AT 23/02/2020 - 04:03 AM


QUESTION POSTED AT 23/02/2020 - 04:03 AM

How could you test to see if soil temperature was responsible for a variation in flower color?

Make a test of experimental groups for flowers with warmer soil and another with regular soil and to be sure cold soil.  

ANSWERED AT 23/02/2020 - 03:17 AM


QUESTION POSTED AT 23/02/2020 - 03:17 AM

The ability to roll your tongue is determined by a dominant gene (R) while recessive gene results in the inability to roll the tongue (r). A man and his wife can both roll their tongues and are surprised to find that thier son cannot. Explain this by showing the genotypes of all three persons

The genotypes of the parents would both be Aa or heterogeneous. Therefore, based on a punnet square, there is a 25% chance that the offspring would have the genotype aa or homogeneous recessive, which occurred. 

ANSWERED AT 23/02/2020 - 02:34 AM


QUESTION POSTED AT 23/02/2020 - 02:34 AM

A dog breed has a pair of alleles that determine curly hair ( c. versus straight hair ( c. given allele frequencies of c = 0.1 and c = 0.9, solve the hardy-weinberg equation to determine the expected frequencies of individuals in the population having genotypes cc, cc, and cc

The hardy-weinberg equation is
p2 + 2pq + q2 = 1
where are already given with
c = 0.1 and C = 0.9
SO
p2 = 0.9^2
p2 = 0.81
q2 = 0.01
0.81 + 2pq - 0.01 = 1
2pq = 0.18
The answers are
CC = 0.81
cc = 0.01
Cc = 0.18

ANSWERED AT 23/02/2020 - 02:11 AM


QUESTION POSTED AT 23/02/2020 - 02:11 AM