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
m_a_m_a [10]
3 years ago
14

Which of the following was not developed until the early part of the twentieth century?

Biology
1 answer:
OleMash [197]3 years ago
3 0

Answer:

Explanation:

absolute time

You might be interested in
The right and left hepatic ducts emerge from the right lobe of the liver in the porta hepatis and unite to form the:
dexar [7]

Answer:

common hepatic duct

Explanation:

  • The common hepatic duct is formed by the union of the right and left hepatic ducts emerging out from the right lobe of the liver.
  • The right hepatic duct is responsible for draining bile from the right half of the body whereas the left hepatic duct drains it from the left side of the body. 
  • At the junction of the right and left hepatic duct, the common hepatic duct gets formed which then joins the cystic duct and then the common bile duct is formed. 
8 0
3 years ago
Acetylcholine receptors on skeletal muscles are described as being ionotropic receptors because
DerKrebs [107]

Answer:

they are Na+, K+ and Ca2+ ion channels.

Explanation:

Ionotropic acetylcholine receptors are also called nicotinic acetylcholine receptors because beside acetylcholine (Ch) they respond to nicotine. These receptors are  primary receptors in muscle for motor nerve-muscle communication that controls muscle contraction.

Two molecules of ACh are required for receptor to open. Since the receptors are  linked to ion channels, the channels open. Opening of the channel allows positively charged ions to move across it: sodium enters the cell and potassium exits.

3 0
3 years ago
Muscles help keep blood flowing normally through the body. How do muscles accomplish this task?
bezimeni [28]

Answer:

Option A, by having a constant supply of blood

Explanation:

Blood that flows to the muscles bring oxygen from the atmosphere to the contracting muscles where it gets consumed.  During large muscle exercise, two physiological needs arise – a) high and prolonged muscle blood flow and b) regulation of blood pressure so that there is adequate perfusion of pressure to all organs. In order to meet both the requirements, the blood flow increases so that the vasoligating muscles do not outstrip the cardiac output.

Hence, option A is correct

6 0
3 years ago
HELP ME PLZ!!!!!!!!!!!!!!!!111111111
Alisiya [41]

Answer:

B I guest but m not so sure..

8 0
3 years ago
Read 2 more answers
Charles washes his hands every time he passes either the bathroom or the kitchen sink. Before he goes to bed at night, he checks
FromTheMoon [43]

In reality this is way too little information to go on, and it would be irresponsible to make any assumptions about an individual based on what was provided here alone, but for the sake of merely answering a High School Bio question:

the answer is  A.  OCD.

3 0
3 years ago
Read 2 more answers
Other questions:
  • Which statement shows an example of how human activities can directly change the equilibrium of an ecosystem? A. A cold front mo
    8·2 answers
  • Living plants may be valuable additions to science classrooms. Which is the most important safety consideration when planning to
    10·2 answers
  • 10 words with out pls help me God well return you the favor
    13·1 answer
  • Photographs are rarely taken at the scene where bones are found. True False
    13·2 answers
  • The lesser tubercle of the humerus is the distal skeletal attachment site for the
    7·2 answers
  • Why split up the letters on top instead of writing both of them in one box? punnet square
    9·1 answer
  • Is the sentence below a true or false statement?
    8·1 answer
  • If a simple pendulum takes 50 seconds to complete 25 oscillations, what is the time period of the pendulum? Write the formula an
    5·1 answer
  • The preganglionic fibers of the sympathetic nervous division originate in segments ____ of the spinal cord and first enter the _
    10·1 answer
  • A species with narrow niches that can survive in a small range of environmental conditions are
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!