Answer:
a boy pulling a toy train, the boy is
interacting with an object while applying a force to it,
another example of contact forces is friction.
Explanation:
A contact force is when two interacting
objects
(btw love your pfp)
Answer: The ions which are not spectator ions are
and
Explanation:
Spectator ions are defined as the ions which does not get involved in a chemical equation or they are ions which are found on both the sides of the chemical reaction present in ionic form.
The given chemical equation is:
The ions which are present on both the sides of the equation are
and
and are spectator ions.
Thus the net ionic equation is:

Hence, the correct answer is
and
Number of atoms : 1.26 x 10²³
<h3>Further explanation </h3>
The mole is the number of particles(molecules, atoms, ions) contained in a substance
1 mol = 6.02.10²³ particles
Can be formulated
N=n x No
N = number of particles
n = mol
No = Avogadro's = 6.02.10²³
0.21 moles of Al, so n = 0.21
Number of atoms :

The bone tissue contains many small pauses this is most likely caused by osteoporosis.
<h3>What is osteoporosis?</h3>
Osteoporosis is a health condition that weakens bones, making them fragile and more likely to break.
Osteoporosis causes bones to become weak and brittle — so brittle that a fall or even mild stresses such as bending over or coughing can cause a fracture.
Osteoporosis-related fractures most commonly occur in the hip, wrist or spine.
Bone is living tissue that is constantly being broken down and replaced.
Hence, the bone tissue contains many small pauses this is most likely caused by osteoporosis.
Learn more about the osteoporosis here:
brainly.com/question/7246059?referrer=searchResults
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Scientists have known the consequences of mixing sodium bicarbonate and vitamin C ever since 1936, when a study on the subject was published in the "Journal of Nutrition." The authors of this study measured the amount of vitamin C recovered from the urine of people who drank a fixed amount of orange juice. The authors determined that the amount of vitamin C excreted was decreased by administration of sodium bicarbonate. Followup studies in the 1940s showed that this effect was due to the neutralization of the vitamin C by the sodium bicarbonate.