1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
e-lub [12.9K]
3 years ago
7

Which of the following is a function of the cell membrane?

Biology
1 answer:
Crazy boy [7]3 years ago
6 0

Answer:

The answer is C.

Explanation:

The cell membrane controls what enters and leave the cell. Therefore, eliminating any waste the cell doesn't need.

You might be interested in
Scientists often use fruit flies as a method to test hypotheses about human genes. Why are fruit flies advantageous in the study
Semmy [17]
Fruit flies share 75% of the genes that cause diseases with humans, so scientists can learn about human genetics by studying fruit fly genetics.
7 0
3 years ago
All evolutionary changes that allow a species to change in response to the environment are originally a result of A) beneficial
Gemiola [76]

Answer: D. adaptations that organisms make to the environment during their lifetimes.

Adaptation is a process in which changes occurs in an organism so as to make it better suited for the environment. It is the result of natural selection. In adaptation the traits of an organism gets modified by the process of natural selection which results in evolution of an organism.  

7 0
3 years ago
Read 2 more answers
Explain Nitrogen cycle [ step by step ]
Len [333]

Explanation:

Nitrogen is essential to life because it is a key component of proteins and nucleic acids. Nitrogen occurs in many forms and is continuously cycled among these forms by a variety of bacteria. Although nitrogen is abundant in the atmosphere as diatomic nitrogen gas (N2), it is extremely stable, and conversion to other forms requires a great deal of energy. Historically, the biologically available forms NO3- and NH3 have often been limited; however, current anthropogenic processes, such as fertilizer production, have greatly increased the availability of nitrogen to living organisms. The cycling of nitrogen among its many forms is a complex process that involves numerous types of bacteria and environmental conditions.

In general, the nitrogen cycle has five steps:

Nitrogen fixation (N2 to NH3/ NH4+ or NO3-)

Nitrification (NH3 to NO3-)

Assimilation (Incorporation of NH3 and NO3- into biological tissues)

Ammonification (organic nitrogen compounds to NH3)

Denitrification(NO3- to N2)

Nitrogen Fixation

Nitrogen fixation is the process by which gaseous nitrogen (N2) is converted to ammonia (NH3 or NH4+) via biological fixation or nitrate (NO3-) through high-energy physical processes. N2 is extremely stable and a great deal of energy is required to break the bonds that join the two N atoms. N2 can be converted directly into NO3- through processes that exert a tremendous amount of heat, pressure, and energy. Such processes include combustion, volcanic action, lightning discharges, and industrial means. However, a greater amount of biologically available nitrogen is naturally generated via the biological conversion of N2 to NH3/ NH4+. A small group of bacteria and cyanobacteria are capable using the enzyme nitrogenase to break the bonds among the molecular nitrogen and combine it with hydrogen.

Nitrogenase only functions in the absence of oxygen. The exclusion of oxygen is accomplished by many means. Some bacteria live beneath layers of oxygen-excluding slime on the roots of certain plants. The most important soil dwelling bacteria, Rhizobium, live in oxygen-free zones in nodules on the roots of legumes and some other woody plants. Aquatic filamentous cyanobacteria utilize oxygen-excluding cells called heterocysts.

Nitrification

Nitrification is a two-step process in which NH3/ NH4+ is converted to NO3-. First, the soil bacteria Nitrosomonas and Nitrococcus convert NH3 to NO2-, and then another soil bacterium, Nitrobacter, oxidizes NO2- to NO3-. These bacteria gain energy through these conversions, both of which require oxygen to occur.

Assimilation

Assimilation is the process by which plants and animals incorporate the NO3- and ammonia formed through nitrogen fixation and nitrification. Plants take up these forms of nitrogen through their roots, and incorporate them into plant proteins and nucleic acids. Animals are then able to utilize nitrogen from the plant tissues.

Ammonification

Assimilation produces large quantities of organic nitrogen, including proteins, amino acids, and nucleic acids. Ammonification is the conversion of organic nitrogen into ammonia. The ammonia produced by this process is excreted into the environment and is then available for either nitrification or assimilation.

Denitrification

Denitrification is the reduction of NO3- to gaseous N2 by anaerobic bacteria. This process only occurs where there is little to no oxygen, such as deep in the soil near the water table. Hence, areas such as wetlands provide a valuable place for reducing excess nitrogen levels via denitrification processes.

Common Forms of Nitrogen

The most common forms of inorganic nitrogen in the environment are diatomic nitrogen gas (N2), nitrate (NO3-), nitrite (NO2-), ammonia (NH3), and ammonium (NH4+). The species that predominate depend on the chemical, physical, and biological environment.

In aquatic environments, the presence of nitrogen as unionized ammonia (NH3) or ammonium (NH4+) is dependent on the pH and temperature.

When the pH is below 8.75, NH4+ predominates. Increases in pH signify increases in the hydroxyl ion (OH-) concentration of the water, meaning the above reaction will shift to the left in order to reach equilibrium. Above a pH of 9.75, NH3 predominates (Hem, 1985). NH3 is a more toxic to aquatic life. If biological assimilation of NH3 is not occurring at a sufficient rate, NH3 may accumulate and cause detrimental effects to aquatic life.

In soils, NH4+ ions are strongly sorbed by clay particles and organic matter, which have a net negative surface charge. In alkaline soils, NH4+ will be converted to NH3 gas, and lost to the atmosphere. Under warm growing conditions, NH4+ in the soil will be transformed to NO3- via nitrification. NO3- is very soluble, and can easily be leached from soils under wet conditions.

3 0
3 years ago
Question 1 of 10<br> What are the basic units of a chemical element called?
ElenaW [278]

Answer:

An atom is the basic unit of a chemical element. Atoms are made out of three main parts: protons, neutrons and electrons. Protons and neutrons are contained inside the very center of the atom, which is called the nucleus.

Explanation:

hope it may help you

6 0
3 years ago
Read 2 more answers
The _________ are a pair of slender ducts through which eggs pass from the ovaries to the uterus in the female reproductive syst
TiliK225 [7]
The correct response is Fallopian tubes, or D
7 0
3 years ago
Read 2 more answers
Other questions:
  • 1. How do different natural phenomena change the surface of the Earth over time?
    12·2 answers
  • What is the most abundant gas in Earth's present day atmosphere
    8·1 answer
  • Clouds form when water vapor in the atmosphere cools to _______.
    15·2 answers
  • In an animal that switches between sexual and asexual reproduction is called
    10·1 answer
  • How do trees prevent flooding​
    11·2 answers
  • HELP QUICK PLEASE!!<br> i think it is B but im not sure
    7·2 answers
  • What are the processes in cellular respiration? ( middle school level)
    8·2 answers
  • Which of the following is a yield from a tree?<br> Roots<br> Timber<br> Branches<br> Vegetables
    15·1 answer
  • A cross between a white horse and a brown horse produces offspring that are golden in color. The possible
    14·1 answer
  • In order to predict how much tension a muscle can produce when contracting, it is important to consider the ______ relationship
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!