Potato spindle-tuber disease, which causes potatoes to become gnarled and cracked, is caused by an infectious agent consisting of a small circular RNA molecule that totally lacks a protein coat. These infectious agents are thought to exert their effects by interfering with the cell's normal path of gene expression. Such an infectious agent is known as a(n):.
a. provirus
b. bacteriophage
c. prion d. viroid
e. girus

d. viriod

Potato spindle-tuber disease, which causes potatoes to become gnarled and cracked, is caused by an infectious agent consisting of a small circular RNA molecule that totally lacks a protein coat. These infectious agents are thought to exert their effects by interfering with the cell's normal path of gene expression. Such an infectious agent is known as a(n): viriod.

Explanation:

Viriods are very small , covalently closed, circular RNA molecules capable of autonomous replication and induction of disease.

They range in size from approximately 20nm and are infectious particles.

They consist only of Nucleic acid (RNA) and exert their effects by interfering with the cell's normal path of gene expression.

They mainly cause diseases in Plants.

As in the potato spindle-tuber disease, the infectious agent has all the characteristics as that of a virioid. Hence Viriod is the right choice.

explanation:

idk

events in order:

1.       vishnu schist

2. zoroaster granite

3. bass limestone

4. hakatar   shale

5. igneous intrusion

6. shinumo quartzite

7. dox sandstone

8. tapeats limestone

9. bright angel shale

10. muav limestone

11. temple butte limestone

12. redwall limestone  

nonconformity

answer: the unkar group shows angular unconformity because the layers are turned at angle.

unconformity

answer: specifically the angular unconformity occurs between the cambrian and precambrian rocks. the dox sandstone, shinumo quartzite, hakatar shale, and bass limestone have been filled. an angular unconformity occurs between the cambrian and precambrian rocks. the dox sandstone, shinumo quartzite, hakatar shale, and bass limestone have been filled.

disconformity

answer: the disconformities aremarked irregular lines between the sedimentaryrocks layers.