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
Varvara68 [4.7K]
3 years ago
14

When the atria contract, which of the following is true? a. The AV valves are closed. b. The ventricles are in diastole. c. The

atria are in diastole. d. The semilunar valves are open.
Biology
1 answer:
gizmo_the_mogwai [7]3 years ago
5 0

Answer:

b. The ventricles are in diastole.

Explanation:

Atrial systole is the phase of the cardiac cycle that lasts for about 0.1 sec. During this phase, the atria are contracting. At the same time, the ventricles are relaxed or are in diastole. The pressure of the contraction of atria forces the blood to open the AV valves. The blood enters the ventricles through the open AV valves. During this phase, the semilunar valves are closed as the blood pressure in ventricles is very low. The P wave of ECG represents the atrial systole. This is followed by the systole of ventricles.

You might be interested in
*HELP*
Alekssandra [29.7K]

Answer: A prokaryotic cell is a simple, single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle. We will shortly come to see that this is significantly different in eukaryotes. Prokaryotic DNA is found in the central part of the cell: a darkened region called the nucleoid Unlike Archaea and eukaryotes, bacteria have a cell wall made of peptidoglycan, comprised of sugars and amino acids, and many have a polysaccharide capsule (Figure 1).

Explanation:

3 0
2 years ago
Calculate the mass defect for oxygen-16 given this data. Round to the 5es001-1.jpg decimal place. mass of an oxygen-16 atom: 15.
Naya [18.7K]

Answer:

Explanation:

Given parameters:

Mass of oxygen atom = 15.994914amu

Mass of a proton = 1.00728amu

Mass of a neutron = 1.00866amu

Unknown:

Mass defect = ?

From the periodic table, the number of the elementary particles in a neutral Oxygen atom is given below:

           Number of protons = 8

           Number of neutrons = 8

          Number of electrons = 8

Solution

The mass defect examines the difference between the actual mass of an atom and sum of masses of the nucleons.

The mass of an atom is concentrated in the nucleus which contains protons and neutrons. Electrons have little to no weight compared with the nucleons.

    To calculate the mass defect, we first know the mass of the nucleons first:

           1 proton has a mass of  1.00728amu

           8 protons will weigh: (8 x 1.00728)amu = 8.05824amu

For the neutrons:

          1 neutron has a mass of 1.00866amu

          8 neutrons will weigh: (8 x 1.00866)amu = 8.06928amu

Mass of the nucleons = mass of protons + mass of neutrons

                                   = 8.05824amu + 8.06928amu

                                   = 16.12752amu

The mass defect = mass of the nucleons - mass of the atom

                             = 16.12752amu - 15.994914amu

                              = 0.132606amu ≅ 0.13261amu to 5 decimal places

6 0
3 years ago
Read 2 more answers
Hbdbd dx d d dbddbbsdbdbdb
inna [77]

Answer:

io4ht3fhiq

Explanation:

7 0
3 years ago
How can scientific conclusions be reliable, but also able to be changed with the introduction of new evidence
aleksklad [387]

Answer:

scientific conclusions are reliable as they are helpful for many things however it is true that after the evolution of new ideas the old theory have some changes or may change fully or may be proved wrong but yeah the old theories are still helpful for many reasons and things.

so I think scientific conclusions are reliable

8 0
3 years ago
Which steroid hormone(s) would not be produced if you blocked the activity of p450scc?
natka813 [3]
P450scc or cholesterol side chain cleavage enzyme is an enzyme that converts cholesterol into pregnenolone (the precursor for steroids). The kinds of steroid hormones are mineralocorticoids (i.e. aldosterone) glucocorticoids (i.e. cortisol), and sex steroids (i.e. testosterone, estrogen). In the event where P450scc is blocked, then there will be no production of mineralocorticoids, glucocorticoids, and sex steroids. There will be no production of aldosterone, cortisol, estradiol, testosterone, and progesterone. This disease is called Lipoid Congenital Adrenal Hyperplasia.
3 0
3 years ago
Other questions:
  • | ANSWER NEED ASAP | Which of these is a disease that testing can be done for in either the parents or the child?
    14·2 answers
  • Salt water is denser than fresh water. What ecosystem would be most affected by this fact? Explain your answer
    5·1 answer
  • Identify the position of the fetus whose buttocks are in the fundus, whose fetal back is on the maternal right side between the
    7·1 answer
  • In comparing stop-transfer and internal start-transfer sequences in proteins, it can be said that __________. In comparing stop-
    8·1 answer
  • Although the atmosphere contains about 78% nitrogen gas, only a few types of organisms are able to convert it into a form usable
    11·1 answer
  • Please select the word from the list that best fits the definition
    13·1 answer
  • What organelle is labeled E? <br><br> Need help on this question
    12·1 answer
  • 18.Cells produced from meiosis contain a single copy of cach chromosome, therefore they are
    11·1 answer
  • Which statement describes an advantage of sexual reproduction?
    8·1 answer
  • Spores and seeds have basically the same function-dispersal-but are vastly different because spores ________. (A) have a protect
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!