Answer;
-B3
Explanation;
Refrigerants are divided into two groups according to toxicity:
-Class A signifies refrigerants for which toxicity has not been identified at concentrations less than or equal to 400 ppm; and
-Class B signifies refrigerants for which there is evidence of toxicity at concentrations below 400 ppm.
They are also divided into three groups according to flammability:
-Class 1 indicates refrigerants that do not show flame propagation when tested in air at 21°C and 101 kPa;
-Class 2 indicates refrigerants having a lower flammability limit of more than 0.10 kg/m3 at 21°C and 101 kPa and a heat of combustion of less than 19 kJ/kg;
-Class 3 indicates refrigerants that are highly flammable as defined by a lower flammability limit of less than or equal to 0.10 kg/m3 at 21°C and 101 kPa or a heat of combustion greater than or equal to 19 kJ/kg.
-Therefore; the answer for the above question would be Class B and class 3.
In the 1800s, Darwin explains the origin of species. As species originate through adaptation by natural selection.
Answer: Species originate through adaptation by natural selection
<u>Explanation:
</u>
The Origin of species through natural selection is a pioneering scientific effort of the British naturalist Charles Darwin in England. Darwin's theory is that organisms are gradually evolving through what is called "natural selection"
It is a process in which organisms change due to hereditary changes in physical or behavioural traits. Changes that allow the body to better adapt to its surroundings, help it survive and have more offspring.
In the f2 generation of mendel's crosses, all plants had the dominant trait,all plants had both the dominant and recessive alleles. one in four plants had two alleles for the recessive trait.
Answer:
a) another living cell
Explanation:
"All living cells arise from pre-existing cells by division."
