Adenine and guanine
Thymine and cytosine
Answer:
Correct
Explanation:
Homeostatic is nothing but ability of a system or living organism to manipulate its internal environment to maintain a stable equilibrium, for example the ability of warm-blooded animals to ascertain a constant body temperature.
The Homoeostatic feedback mechanism has three basis components and they are independent to one another.
These components are receptor, effector and integrating center. The function of receptor is to sense external stimuli and send information to integrating center. The integrating center generally hypothalmus in brain sends this signal to effector for example an organ to react to the stimuli.
So, the order in a homeostatic feedback system stimulus, receoptor, control centre, effector is correct.
Mutations are not a mechanism for evolution.
The correct answer is A.
Animal cells do not have a cell wall.
A cell wall is the rigid, outermost covering of plant cells and is made up of cellulose. It is absent in animal cells. The cell wall is visible under a light microscope.
Animal cells are instead covered by a cell membrane. It is made up of lipids, proteins, and small amounts carbohydrates. It is a thin and delicate structure that can only be seen using an electron microscope.
