Greg and Andrea are trying to find out how long it takes amylase, a digestive enzyme found in saliva, to break down a sample of starch. They put their sample in a beaker and covered it with their own saliva. After allowing it to sit on the lab table for 1 hour they measured the remaining surface area of the starch. What is the best way they could improve their experiment?

QUESTION POSTED AT 18/01/2020 - 07:36 AM

Answered by admin AT 18/01/2020 - 07:36 AM

The answer is: the amount of the saliva samples must stay consistent while the amount of starch must vary.

The amount of the saliva samples must stay consistent because amylase, present in the saliva, is the independent variable which affects the dependent variable - the amount of starch. So, amylase will do its job while remaining surface area of the starch will depend on the starting amount of the starch.
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The mineral particles found in the layers of a soil, including the topsoil and subsoil layers, were originally weathered from

Acid rain. The rain would have weakened the soil.

ANSWERED AT 24/02/2020 - 12:35 AM

QUESTION POSTED AT 24/02/2020 - 12:35 AM

Chromosome is to DNA as hour is to what?

Chromosome is to DNA as hour is to minute.

ANSWERED AT 24/02/2020 - 12:07 AM

QUESTION POSTED AT 24/02/2020 - 12:07 AM

If you watch a star other than Polaris for two hours, how many degrees will it appear to rotate in the sky during that time? Select one: a. 60 degrees b. 0 degrees c. 15 degrees d. 30 degrees

A star moves 15 degrees each hour, so it would’ve moved 30 degrees in two hours.

D, 30 degrees.

ANSWERED AT 23/02/2020 - 11:54 PM

QUESTION POSTED AT 23/02/2020 - 11:54 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


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.


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

Do plants such as Ferns need to break down glucose in order to obtain energy

No they absorb the sun's energy directly.
Hope this helps

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

Which of the following can lead to coral bleaching? a. long-term temperature variations b. increased solar radiation c. freshwater dilution d. all of the above


a. long-term temperature variations


  • As a result of the long term warming of the global temperatures of the oceanic waters, the corals will expel the algae that are the zooxanthellae from their tissues causing them to turn white and hence cause coral bleaching.
  • Hence becomes vulnerable to diseases and affects there reproduction and stunts the growth cycle.

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

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


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

What do sea stars have on the bottom of their feet that allows them to stay anchored on a rock or at the bottom of the ocean? A. suction cups B. tube feet C. madreporite D. radial symmetry

The answer is B. tube feet

The tube feet on a starfish helps it anchor to surfaces.

Trust me I just dissected one! eww

Have a good day! =)

ANSWERED AT 23/02/2020 - 11:03 PM

QUESTION POSTED AT 23/02/2020 - 11:03 PM

Where in the body can you find connective tissue?

Connective tissue is based up off of four different types of cells 1) adipose which is fat 2) dense fibrous which makes up cartilage ligaments and tendons. Connective tissue is also found in 3) bone tissue which is your skeleton and 4) Vascular cells which is a component of blood.

so it's found through our the body in places like fat, tendons ligaments, cartalige, your bones, and in your blood. hope that gives you some ideas

ANSWERED AT 23/02/2020 - 10:57 PM

QUESTION POSTED AT 23/02/2020 - 10:57 PM

The ancient fossils are a record of when shallow seas covered much of the United States. While the fossils are of organisms that are the precursors of many modern day organisms, changes in ocean geography and other factors eventually caused those older species to become __________.

-It is considered to be the link between the lobe-finned fishes and early ... Climate andgeography ... Sea levels were high with much of western North America under water. ... By the mid-Devonian, the fossil record shows evidence that there ... Plants, which had begun colonizing the landduring the Silurian ...

ANSWERED AT 23/02/2020 - 05:01 AM

QUESTION POSTED AT 23/02/2020 - 05:01 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

What is meant by homologous chromosomes? chromosomes are found in pairs the gene's alleles are found in matched chromosome pairs all chromosomes contain the same genes each homologous chromosome has identical genotypes


Chromosomes are found in pairs


Homologous chromosomes are chromosome pairs similar in lenght, gene positioning and centromere location but non-identical. They are donated by each parent (make and female). They are non-identical in the sense that the alleles on each pair may be different. For example, the chromosome donated by a female pea plant may contain a yellow allele for a particular gene while that donated by the male pea plant may contain a green allele.

A karyotype (a pictorial display of chromosomal arrangement) shows that in a diploid organism like humans, chromosomes are in two complete sets. Each human cell contains 23 pairs of chromosomes in which every chromosome pair represents a set of homologous chromosomes.

In each pair of chromosome, one chromosome is contributed by the male parent while the other by the female parent. In total, each parent contributes 23 chromosomes via gametes to form a total of 23pairs or 46chromosomes.

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

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

Approximately how long did it take from the time the first feather evolved until the first animal took flight? A. 1 million years B. 1000,000 years C. 50 million years D. 500 years

The answer is C. 

It took approximately 50 million years for feathers to evolve into being able to be used for flight. It started with dinosaurs running up an incline and flapping their feathered arms to provide extra speed. To gliding short distances from a high point. To the ability to fly short distances. To the ability to fly far distances (modern birds). This process took 50 million years.

Hope this helped. Have a great day!

ANSWERED AT 22/02/2020 - 07:05 PM

QUESTION POSTED AT 22/02/2020 - 07:05 PM

The three domain system arose when scientists found that eubacteria and archaebacteria were more a. like eukaryotes b. similar then scientists thought c.dissimilar then scientists thought fungi

Answer : The correct answer is- c.dissimilar then scientists thought.

The three-domain system recognizes basic differences that are present with two groups of prokaryotes, which are archaebacteria and eubacteria.

According to this system, life forms are divided into three distinct domains that are Archaebacteria, eubacteria and Eukarya based on the differences in the rRNA (ribosomal RNA) sequences, lipid structure in their cell membrane, and antibiotic sensitivity.

This system of classification arose when scientist found that the eubacteria and archaebacteria were more than they thought.

For instance, archaebacteria are single celled microscopic prokaryotes that mainly live in harsh environmental conditions (like hot springs) whereas eubacteria do not live in such conditions.

ANSWERED AT 22/02/2020 - 07:03 PM

QUESTION POSTED AT 22/02/2020 - 07:03 PM

The usefulness of mendeleev's periodic table was confirmed by

The discovery of a variety of elements with predicted properties explains the effectiveness of the periodic table.

Further Explanation:

Dmitri Ivanovich Mendeleev is a scientist from Russia; he mainly contributes to explaining the periodic table or help in developing the periodic table. The periodic table is also referred to as Mendeleev periodic table. In his table, all the elements which have been identified are organized based on mass, chemical properties, and fundamental properties of an element.

Also, from the periodic table, he determined that all the properties of the element are relatable to the atomic mass of an element. He also arranges all the elements in such a manner that elements that have similar properties are grouped in the same column. In the table, the molecule of hydrogen is not very well explained with its properties.

Newly discovered elements can easily be added to the table because some columns yet to be vacant for new elements. The effectiveness of the periodic table is explained by new research on a variety of elements.

Learn more:

  1. Learn more about cellular respiration
  2. Learn more about diffusion
  3. Learn more about phospholipids bilayer

Answer Details:

Grade: High School

Subject: Biology

Chapter: Respiration

Keywords: Element, properties, Russia, column, periodic table, variety, effectiveness, Mendeleev, mass, chemical properties, fundamental, arrange, manner.

ANSWERED AT 22/02/2020 - 07:01 PM

QUESTION POSTED AT 22/02/2020 - 07:01 PM

There are health concerns surrounding the products that have been genetically engineered for particular traits, including pharmaceuticals, crops, and enzymes that are used in industry and manufacturing processes. Which is a health concern that affects society? A Patented Products B bioaccumulation C Land use D Cancer

Cancer is a health concern that affects society

Cancer is a group of diseases that are characterized by the rapid growth of abnormal cells that divide uncontrollably and have the ability to spread and damage the normal body tissue. Cancer can occur anywhere in the body, and is rated as the second leading cause of death in the United States. There are many types of cancer, they include; breast cancer, prostate cancer, skin cancer, lung cancer, colon cancer, and lymphoma. The symptoms of cancer differ, and it depends on the type.

ANSWERED AT 22/02/2020 - 07:01 PM

QUESTION POSTED AT 22/02/2020 - 07:01 PM

Will be BRAINLIEST if answered fast What does finding a balance in the use of drones mean? Is FAA working to find a balance? why?

In this article, professor Hillary Farber talks about 'finding balance' in the use of drones by this she means that we need to find a way that we can use drones and have privacy and be safe. I believe that FAA is working to find a balance because they created new rules for the use of drones. Also, they created a national drone registry or list.

ANSWERED AT 22/02/2020 - 06:51 PM

QUESTION POSTED AT 22/02/2020 - 06:51 PM