Concept explainers
Test your Understanding
Know and Comprehend
A radially symmetrical animal such as Hydra is likely to have (a) a forebrain (b) a nerve net (c) cerebral ganglia (d) a ventral nerve cord (e) cerebral ganglia and a nerve net
Introduction: Hydra is a freshwater organism of the phylum Cnidaria. They have very high regenerative ability. They are radially symmetrical invertebrates and have tentacles to capture their food.
Answer to Problem 1TYU
Correct answer: Radially symmetrical organisms such as Hydra have simple nervous systems like the nerve net. Hence, the correct answer is option (b).
Explanation of Solution
Reason for the correct answer:
Radial symmetry is generally present in simpler organisms such as Hydra. Organisms belonging to simpler classes in the animal kingdom have less complexed nervous systems. They usually have interconnected networks of neurons, and no central control system is present in such simpler neural systems. Such connection of neurons forms the nerve net.
Option (b) is given as “a nerve net”.
Radially symmetrical organisms such as Hydra have simpler body organization and simpler nervous systems such as the nerve nets. Hence, the correct answer is option (b).
Reasons for incorrect answers:
Option (a) is given as “a forebrain”.
A forebrain is a part of a complex nervous system that is found in higher organisms with a complex body organization. The forebrain is not found in simpler organisms such as Hydra. Hence, option (a) is incorrect.
Option (c) is given as “cerebral ganglia”.
Radially symmetrical organisms have simple nervous systems that do not have any control center. Cerebral ganglia act as a control center in the nervous systems. Hence, option (c) is incorrect.
Option (d) is given as “a ventral nerve cord”.
Ventral and dorsal sides can be defined only in organisms with bilateral symmetry. In organisms with simple body organization, there is no nerve cord present. Thus, radially symmetrical organisms cannot have a ventral nerve cord. Hence, option (d) is incorrect.
Option (e) is given as “cerebral ganglia and a nerve net”.
Simpler organisms do not have cerebral ganglia in their nervous systems. Hence, option (e) is incorrect.
Hence, options (a), (c), (d), and (e) are incorrect.
Organisms with radial symmetry in their body organization, such as Hydra, have a nervous system consisting only of nerve nets.
Want to see more full solutions like this?
Chapter 42 Solutions
Biology (MindTap Course List)
- 18. Watch this short youtube video about SARS CoV-2 replication. SARS-CoV-2 Life Cycle (Summer 2020) - YouTube.19. What is the name of the receptor that SARS CoV-2 uses to enter cells? Which human cells express this receptor? 20. Name a few of the proteins that the SARS CoV-2 mRNA codes for. 21. What is the role of the golgi apparatus related to SARS CoV-2arrow_forwardState the five functions of Globular Proteins, and give an example of a protein for each function.arrow_forwardDiagram of check cell under low power and high powerarrow_forward
- a couple in which the father has the a blood type and the mother has the o blood type produce an offspring with the o blood type, how does this happen? how could two functionally O parents produce an offspring that has the a blood type?arrow_forwardWhat is the opening indicated by the pointer? (leaf x.s.) stomate guard cell lenticel intercellular space none of thesearrow_forwardIdentify the indicated tissue? (stem x.s.) parenchyma collenchyma sclerenchyma ○ xylem ○ phloem none of thesearrow_forward
- Where did this structure originate from? (Salix branch root) epidermis cortex endodermis pericycle vascular cylinderarrow_forwardIdentify the indicated tissue. (Tilia stem x.s.) parenchyma collenchyma sclerenchyma xylem phloem none of thesearrow_forwardIdentify the indicated structure. (Cucurbita stem l.s.) pit lenticel stomate tendril none of thesearrow_forward
- Identify the specific cell? (Zebrina leaf peel) vessel element sieve element companion cell tracheid guard cell subsidiary cell none of thesearrow_forwardWhat type of cells flank the opening on either side? (leaf x.s.) vessel elements sieve elements companion cells tracheids guard cells none of thesearrow_forwardWhat specific cell is indicated. (Cucurbita stem I.s.) vessel element sieve element O companion cell tracheid guard cell none of thesearrow_forward
- Biology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage LearningBiology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage Learning
- Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxBiology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781305073951Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage Learning