INTRODUCTION
Background to the Study
Biology is basic for understanding the complexities of life. This aspect of science for example genetically  making significant contribution such as genetically modified foods to many of the inventions that are shaping modern day, and has helped to explain many of the events being encountered in everyday life for example . Despite its importance, biology remains the least pass rate at WAEC and NECO exams science subject among students generally. In Nigeria universities for example, biology departments and Teacher Education in biology continue to witness paucity of students, which is the reason there is serious shortage of biology teachers in secondary schools.
Educators agree that students learn best  when biological concepts are well explained. Also, students’ perceptions about a subject influence their understanding and learning of that subject (Gebbels,Evans and Murphy, 2010), and continuing study of the subject(Williams, Stanisstreet, Spall,  Boyes,2013).This is suggestive that a major reason underpinning students’ participation in a learning task is their perception of it as interesting/boring, or easy/difficult, or relevant. There is evidence that students who find a subject interesting tend to choose it for further study (Williams et al,2013). Thus, for those students who perceive biology concept to be  as difficult, studying it might just be routine and there is less likelihood that the knowledge will be beneficially utilized, not to mention continuing study. This has serious implications for building a pool of biologist that are required for shaping life development, and in particular, biology teachers that would help to build  a strong foundation for the subject in school.
There are many reasons why students have difficulties in learning biological concepts (Zeidan, 2010). The nature of science itself and its teaching methods are among the reasons for the difficulties in learning science, while according to Lazarowitz and Penso (2011), the biological level of organization and the abstract level of the concepts make learning biology difficult. Overloaded biology curricula, the abstract and interdisciplinary nature of biological concepts, and difficulties with the textbooks are the other factors preventing students from learning biology effectively (Tekkaya, Jerime & Jackson 2011). Overloaded biology curricula may not contribute to students’ achievement and lead them to learn the material through memorization. This, of course, prevents meaningful learning. Designing learning environments while ignoring students’ interests and expectations causes several learning problems as well as decreasing their interest in biology (Zeidan, 2010).
Fraser (2012) indicates that there is a close relationship between students’ perceptions of their classroom learning environment and their success. Osborne and Collins (2011) also report that students’ diminishing interest in learning biology is due to the curriculum content being overloaded and not generally related to working life, the lack of discussion of topics of interest, the absence of creative expression opportunities, the alienation of science from society and the prevalence of isolated science subjects.        Biological science includes many abstract concepts, events, topics and facts that students have to learn. This makes it hard for students to learn them (Saka, 20016; Durmaz, 2017). Teachers’ styles of biology teaching and teaching methods and techniques may also be factors that affect students’ learning in biology (Çimer, 2014). In a situation where students are not happy with the way  biology is taught, may affect their interest and  attitudes towards biology and its teaching.
Though Biological knowledge has played a very important role in the society. It has been used to solve problems of diseases and poor yields in agriculture by production of disease resistant and high yielding plants and animals; overpopulation through the development of hormone based contraceptives; protection and management of the environment. (Maundu, Sambili and Muthwii, 2015;Campbell & Reece, 2002). Despite this importance, the performance of students in Nigeria National Examinations Council has been poor. For instance,  students scored a mean of 29.23% in 2010 in  WAEC examination or SSSCE west African Examination. This underachievement in Biology has been attributed to student related factors (KNEC, 2011), teacher related factors (CEMASTEA,2011). It is against this backdrop that this study is aimed at investigating perceived difficulties of some biological concepts experience by senior secondary students in Awka South L.G.A.
Statement of the Problem                          ÂÂ
Scholars in science education believe that teachers have a crucial role in implementing reform in schools and classrooms (Levitt, 2012). According to Aubusson and Watson (2013) teachers have a critical influence on the quality of teaching and learning that occurs in the classrooms. If teachers are willing and positive about trying new initiatives, the chance of successfully making students overcome the difficult experience in the subject will be minimized. Studies have also shown that there is a relationship between student perception of learning environment and attitude of student toward subject (Cakiroglu, Telli and Cakiroglu, 2013). Despite some level of adequate learning environment, students still fail biological subject and are not much motivated to continue studying the subject. This problem has made the level of student inclined to study biological courses in our institution to keep decreasing each year.
Further, studies on the perception of difficulties of some biological concepts by secondary school student have not being effectively explored in order to address the issue of poor performance of students in biological subject. It is against the foregoing that necessitated this study into investigating the perceived difficulties of some biological concepts experienced by senior secondary students in Awka South L.G.A.
ÂÂ
ÂÂ
Purpose of the Study
The purpose of the study is to investigate the perceived difficulties of some Biological concepts experienced by senior secondary students in Awka South L.G.A. Specifically, the study will ascertain.
Significance of the Study
The study will benefit secondary school student, teachers and future researchers.
Secondary school student will benefit from the study as the study highlight some suitable strategies that are effective in teaching biological concepts that are perceived by students as being difficult. It will also help student to come to appreciate the biological concepts and be motivated to study the subject.
Teachers will benefit from this study as the study will help them see the extent to which biological concepts perceived to be difficult for student has hampered their ability to learn biological course. It will also help teachers to effectively use the suitable strategies in that can help student learn biological subject and benefit from it.
Future researchers, will benefit from the study as the study will serve as source of material and reference for related studies.
ÂÂ
ÂÂ
Scope of the Study
The scope of the study covers perceived difficulties of some biological concept experiences by senior secondary students in Awka South L.G.A. The study will also cover biological scheme  perceived as difficult by student, The extent this biological concept affect the learning of biology, the perception of students toward the biological concepts and the effective strategies suitable for teaching the biological concepts perceive to be difficult by students. It will focus on senior secondary school student (SS1 to SS 2).
Research Questions
To achieve the purpose of the study, the following research questions are posed to guide the study.
To what extent has this biological concept affect