Answer to Question 1
Systems development is difficult and risky because system requirements are often very
difficult to determine. Even more difficult, systems development aims at a moving target.
Requirements change as the system is developed, and the bigger the system and the longer the
project, the more the requirements change. Systems development also faces difficulties in terms
of scheduling and budgeting. It is often difficult to estimate the time taken to build a system. It is
essential to determine the cost of developing a system, and if labor hours cannot be estimated,
labor costs cannot be estimated. Yet another challenge is that while a project is underway,
technology continues to change. Unfortunately, as development teams become larger, the
average contribution per worker decreases. This is true because as staff size increases, more
meetings and other coordinating activities are required to keep everyone in sync. There are
economies of scale up to a point, but beyond a workgroup of, say, 20 employees, diseconomies
of scale begin to take over.
Answer to Question 2
B
Occurrence of stem cells at different stages of mammalian development
Living systems such as the human body consist of closely interrelated elements
Embryo and fetal development during weeks 1–25 of gestation.
Children and Their Development, Third Canadian Edition
Sensory systems and Endocrine system
Early stages of embryonic development in Drosophila