Answer: D) The amount of air in a room never changes.
Explanation: Equilibrium is defined as the state in which the concentration of reactants and products is constant or the rate of forward direction is equal to the rate of backward direction.
a) The percentage of nitrogen gas in a room decreases steadily: the amount decreases that means the reaction is taking place in one direction and hence the reaction is not in equilibrium.
b) A blade of grass grows taller : the plant gets taller that means the reaction is taking place in one direction and hence the reaction is not in equilibrium.
c) The amount of water in a cup decreases as it evaporates: The amount of water is decreasing that means the reaction is taking place in one direction and hence the reaction is not in equilibrium.
d) The amount of air in a room never changes: the amount of air does not change as the amount of air leaving the room is same as that of the air entering the room and hence the reaction is in equilibrium.
Chromosome are thread-like structure of DNA and protein found in the nucleus of living cells. They carry the genetic material.
Chromosome cross over occurs between prophase 1 and metaphase1 of cell division during meosis. It is the process in which homologous chromosomes pair up with each other and exchange different portion of their genetic material thereby forming recombinant chromosomes.
As the cell division progresses, the pair of homologous chromosomes are divided in half to form haploid cells. This random process is called assortment.
Mutation occurs when there is any form of alteration in the genetic sequence of a chromosome. During cell division, chromosomal mutation can occur. It can be in form of insertion, duplication, deletion or inversion.
Answer;
-Damage may occur if the tachometer's needle enters the red zone
Explanation;
A tachometer is a sensor device used to measure the rotation speed of an object such as the engine shaft in a car, and is usually restricted to mechanical or electrical instruments.
Tachometer
, indicates the engine revolutions per minute. Damage may occur if needle enters red zone. The “redline” on a tachometer indicates that engine speeds above that value are likely to cause damage to the engine, especially if operated continuously at that speed for more than a few seconds.
In stage 1, both birthrate and death rate are high, and the population grows slowly. Stage 1 describes the US for the early years of history. Then during Stage 2, improvements in health care, sanitation, and nutrition all people to live longer and reduce the death rate. The birthrate however, remains high during this stage so the population increases rapidly. This occurred in the US in the 1800s. Eventually, birthrate decreases to match the low death rate and the population growth slows and eventually stops. This is the US today.
