Question

the endosymbiont theory holds that mitochondria were originally bacteria - like single - celled organisms. which of the following facts support this theory?
i. mitochondria carry out aerobic respiration
ii. mitochondria have their own dna
iii. different cells contain different numbers of mitochondria
iv. mitochondria reproduce themselves independently
a. i and ii only
b. ii and iv only
c. i, ii, iii, and iv
d. ii and iii only

Explanation:

• I: If mitochondria were originally bacteria - like single - celled organisms, it supports the endosymbiont theory.
• II: Bacteria can perform aerobic respiration, and mitochondria's ability to do so is consistent with the theory.
• III: Having their own DNA is characteristic of independent organisms like bacteria, supporting the theory.
• IV: Independent reproduction is also a trait of free - living organisms, supporting the endosymbiont theory.

Answer:

C. I, II, III, and IV