D. A struggle for existence is apparent.
If a struggle for existence is apparent, natural selection occurs because all of the weak/unfit/unadapted ones die.
Answer:
e) Invertebrates lack a nervous system
Explanation:
One of the main characteristics of invertebrates is that they don't have a backbone. Backbones belong to the skeletal system. A totally different story is the nervous system which runs inside the backbone. Although the more complex nervous systems appear in vertebrates the simply fact of having eyes like crabs or insects implies having a nervous system that can control them.
Answer:
Biology is the study of life. The word bio means life, ology means the study of.
Explanation:
I'm not sure if this is what you were looking for but this is the definition
Answer:
B: Energy
Explanation:
Sorry, I'm not COMPLETELY sure it's this, but yeah, try it!