Answer:
Electron
Explanation:
The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.
Symbol= e-
Mass= 9.10938356×10-31 Kg
It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.
He constructed the glass tube and create vacuum in it. He applied electric current between electrodes. He noticed that a ray of particles coming from cathode to wards positively charged anode. This ray was cathode ray.
Properties of cathode ray:
The ray is travel in straight line.
The cathode ray is independent of composition of cathode.
When electric field is applied cathode ray is deflected towards the positively charged plate.
Hence it was consist of negatively charged particles.
While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.
Symbol of proton= P+
Symbol of neutron= n0
Mass of proton=1.672623×10-27 Kg
Mass of neutron=1.674929×10-27 Kg
Answer: Roundworm is refered to as parasite because it harms it host.
Explanation: Roundworm belongs to nematodes, they have two openings mouth and anus,with segmented body,it derives it nutrients by attaching itself to internal organs of it host by and suck the host nutrients.example of Roundworm is Ascaris
Enzymes, to eat their nutrients and get energy from them.
According tom Lichens, represented by this symbiotic relationship, are responsible for primary succession <span>or the establishment of a new site for plant growth. The correct option among all the options that are given in the question is the first option or option "A". I hope the answer has helped you.</span>
