Question

Assertion
Yeasts are unicellular fungi that are used in bakery and brewery industries
Reason
Potato spindle tuber disease is caused by viroids.
A.Both assertion and reason are correct and reason is the correct explanation for assertion.
B.Both assertion and reason are correct but reason is not the correct explanation for assertion
C.Assertion is correct but reason is incorrect
D.Both assertion and reason are incorrect

Answer 1

Hint: Yeasts are eukaryotic organisms and are single-celled microorganisms placed in the kingdom of fungi.
The first yeast organisms originated hundreds of millions of years ago, and at least 1,500 species are currently recognized.
They are estimated to constitute 1% of all known fungal species.

Step by step answer:Yeasts are unicellular organisms that develop from multicellular organisms and in this some species have the ability to develop into multicellular characteristics by forming strings of connected budding cells known as pseudohyphae or false hyphae.
Yeast sizes vary greatly, depending upon the species and environment involved, generally measuring 3–4 µm in diameter, and some yeasts can grow to 40 µm in size.
Most yeasts reproduce asexually with the help of mitosis, and many do so by process known as budding.
With their single-celled growth habit, yeasts can go against molds, which may grow hyphae.
Fungal species that can take both forms (depending on temperature or other conditions) are called dimorphic fungi.
Uses of yeast are as follows:
1.Alcholic beverages like beer and wine
2.Baking
3.Bioremediation
4.Industrial alcohol production
5.Non alcoholic beverages
6.Nutritional supplement
7.Probiotics
8.Aquarium hobby
9.Yeast extract
10.Genetically engineered biofactories
Viroids are the smallest pathogenic organisms and are composed of short strands of circular, single strand of RNA.
They can cause various diseases, such as potato spindle tubers.

So, the correct option is option B.Both assertion and reason are correct but reason is not the correct explanation for assertion.

Note: Yeasts are chemoorganotrophs, as they use organic compounds as a source of energy and do not require sunlight to grow.
Carbon is obtained mostly from hexose sugars, such as glucose and fructose, or disaccharides such as sucrose and maltose.
Some species can metabolize pentose sugars such as ribose,alcohols, and organic acids.