The correct answer is:
A positively charged nucleus is surrounded by one or more negatively charged electrons
The explanation:
when:
proton is a positively charged elementary particle that is a fundamental constituent of all atomic nuclei.
neutron is a subatomic particle found in the nucleus of every atom except that of simple hydrogen. The particle derives its name from the fact that it has no electrical charge
electron is a negatively charged subatomic particle. It can be either free (not attached to any atom), or bound to the nucleus of an atom .
so, , there are positively charged protons and zero-charged neutrons in the nucleus of an atom. Therefore, the nucleus is positively charged, Surrounding the nucleus, the electrons have negative charge.
Thus, the correct answer is (3): A positively charged nucleus is surrounded by one or more negatively charged electrons is correct.
Answer:
Ai --> Bii
Aii --> Bi
Aiii --> Bv
Aiv --> Biii
Av --> Biv
Explanation:
For Ai, naphthalene sublimes directly from a solid to gas when heated at around 80 degree Celsius.
For Aii, Ozone has a molecular formula of O₃.
For Aiii, weeds are normally considered as "unwanted" plants. Many people may consider using herbicides to clear the weeds in their gardens.
For Aiv, filtration is a physical method for separating solid and liquid from a mixture. A filter paper is normally used, in which the complex structure of the paper only allows fluid to pass through it, but not the solid ones. The solid left behind on the filter paper is called "residue".
For Av, photosynthesis is a chemical reaction that occurs in the leaves of a plant, which produces food for plants to survive. Carbon dioxide, water and light are required for photosynthesis to take place.
Answer:
pill need to taken for completing dosage of 
mg
Explanation:
Total dosage of medicine to be taken in a day
mg
Total weight of one pill 
mg
Number of pills required is equal to total dosage of medicine divided by the weight of one pill.
Hence,
Number of pills
They are non-renewable resources that formed when prehistoric plants and animals died and were gradually buried by layers of rock.
