Through my research I found matching questions with similar answers:
A) macrophages
B) antigens
C) antibodies
D) lymph
The best answer to fill in the blank would be the third option C) Antibodies which in the name anti means against, so since the word anti is the same as against, its a battle between antibodies and invaders, so that's why its C).
Generally, the excretory system of the chickens is actually a biological system that usually removes excess of unnecessary materials from the body of the chicken. A function that eliminates the waste product of metabolism in the body such as liquids or gaseous wastes like urine, sweat and exhalation, these substances are usually toxic for the chicken body. There are only several organs that are considered part of the excretory system. It has also said that the system had a closed relationship with temperature in the body.
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.