Which of the following is the most complex according to their cellular level of organization?
Heart
Hair
Euglena
Hydra
Explanation
No explanation available
Video Explanation
Post your Contribution
Discussions (40)
please i don't agree with this answer in any and every logical way....how can the hair be more complex than the heart...Are you guys conforming to what those jamb past questions and answers books say rather than applying simple logic....please who ever answered this question should elaborate, let me know if am missing something
Integumentary system are hair, snail and scales e.t.c
So hair is a system (integumentary system) which means it is the highest in the level of organization
Option B is correct
What does "cellular level of organization" mean?
It refers to how cells in a living thing are structured and grouped to perform life functions. The more specialized and structured the cells are — forming tissues, organs, and systems — the more complex the organism or part is.
---
Now let’s analyze each option in full depth:
---
A. Heart – Correct Answer
- The heart is a vital organ in complex animals (including humans).
- It is made up of multiple types of tissues:
- Cardiac muscle tissue (for contraction)
- Connective tissue (for support)
- Epithelial tissue (lining surfaces)
- Nervous tissue (to regulate heartbeat)
- These tissues are made from highly specialized cells.
- The heart does not function in isolation — it is part of the circulatory system, which works with other systems (like respiratory, nervous).
- Level of organization:
*Cells → Tissues → Organ → Organ System → Organism*
- This makes it highly complex, especially in terms of cellular and functional structure.
---
B. Hair
- Hair is made primarily of keratin, a protein.
- The hair shaft is composed of dead cells that have no internal organelles or function.
- Only the hair follicle (in the skin) has living cells, but even that is very basic in function.
- It doesn't form tissues or organs in the way the heart does.
- Level of organization:
Cells (mostly dead) → Structure
- It lacks complexity in terms of living, functioning cells.
---
C. Euglena
- Euglena is a unicellular organism, meaning it is just one cell.
- It does show internal complexity:
- It has organelles like a nucleus, chloroplasts, and a flagellum.
- It can perform both photosynthesis (like a plant) and move/swim (like an animal).
- However, being unicellular, it has no tissues, no organs.
- Level of organization:
Single cell with organelles
- Complexity is internal but limited to cellular level only.
---
D. Hydra
- Hydra is a simple multicellular animal.
- It has two cell layers:
- Ectoderm (outer) and endoderm (inner)
- With a jelly-like layer (mesoglea) in between.
- Has some tissue-like structures — muscle-like and nerve-like cells.
- Performs basic functions like feeding, movement, and regeneration.
- However, it lacks true organs and complex systems.
- Level of organization:
Cells → Tissues (basic)
- More advanced than Euglena but still less complex than the heart.
---
Conclusion: Why Heart is the Most Complex
- Among all options, only the heart has:
- True tissue and organ-level organization
- Multiple types of specialized cells
- A role within a larger organ system
- Therefore, in terms of cellular structure, specialization, and organization, the heart is the most advanced and complex.
The ans is HAIR....from d enlisted option we
notice...euglena is made of cell which is d least.
hydra is made of tissue
heart is an organ
and hair fall under intergumetary system(which are skin,nails,hair,mammary gland,sweat gland) key point.
however to justify dis point...Hiar is d key feuture that categorize higher organism primate...primate are mammals that possess hair...dat it is seen jxt in man,gorilla,etc...nt all organism possess dis feature...fishes,amphibian,reptile which are multicellular dont have hair...however the heart is seen in majority of them in as much it varies in chamber...they posses heart...even some lower level organism possess heart
unlike hair..remember hair is an intergumetary system...if u doubt find out urself...myschool pls correct this.
txns
Guys please If you don't know the answer just keep quiet and stop causing unnecessary confusion by guessing answers.
EUGLENA is a unicellular organism and exists as a CELL (cell level of organisation)
HYDRA is a multicellular cellular organism which exist at TISSUE level
HEART is an organ made up of cardiac tissue. It exist at ORGAN level
HAIR is made of tissues and it's classified as the INTEGUMENTARY SYSTEM (system level of organization)
The SYSTEM is the highest and most complex level of organisation. Therefore, the answer is B (THE HAIR)
For more clarity please consult your textbook or better still use that phone in hand and search for the level of organisation of each of the options. Biology is not my mate.
MYSCHOOL please correction is required.
Hydra is the most complex among the options provided because it is a multicellular organism belonging to the phylum Cnidaria. It possesses specialized cells organized into tissues, such as epithelial cells, nerve cells, and muscle cells, allowing for more intricate cellular interactions and functions compared to the other options.
While the heart (option A) is a complex organ composed of various types of cells, it is still part of a larger multicellular organism (the human body), and its complexity does not surpass that of Hydra at the cellular level. Similarly, hair (option B) is made up of specialized cells, but it lacks the organized tissue structure found in Hydra. Euglena (option C) is a single-celled organism, so it has a simpler cellular organization compared to Hydra, which is multicellular. Therefore, Hydra stands out as the most complex among the options provided in terms of cellular organization.
The biological levels of organization of living things arranged from the simplest to most complex are: The biological levels of organization of living things arranged from the simplest to most complex are: Organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere
Currently preparing for the upcoming utme and in my own opinion its between the heart and the hydra but if u do like an extensive research they said acccording to cellular level .The answer is hydra because it can exist as an independent,multicellular organism and made up of complex cells while heart is an organ on its own but its still composed of combinations of specialized tissues like epitheal tissues,nerve tissues
Euglena exists at d cellular level, hydra exists at d tissue level, heart is an organ as for hair i don't know. but I think d answer is A... check Essential Biology pg 6/7
