Question

Like embryonic germ cells, which are cells that develop early in the formation of the fetus and that later generate eggs or sperm, embryonic stem cells have the ability of developing themselves into different kinds of body tissue.

• A. embryonic stem cells have the ability of developing themselves into different kinds of body tissue.
  
• B. embryonic stem cells have the ability to develop into different kinds of body tissue
• C. in embryonic stem cells there is the ability to develop into different kinds of body tissue
• D. the ability to develop themselves into different kinds of body tissue characterizes embryonic stem cells
  
• E. the ability of developing into different kinds of body tissue characterizes embryonic stem cells

Answer 1

The correct option is B embryonic stem cells have the ability to develop into different kinds of body tissue

In this question, selection of correct answer lies on the knowledge of correct idiom and not mere conciseness. “Ability of” and “ability to” both are correct expressions. However, they are used differently.
“Ability of” is generally followed by a “proper” noun. This noun can be a person, an organization, a group, a thing, etc. Here we are not talking about a noun form of any word or a gerund.
When we use "ability to, it is followed by a verb.

This sentence is clearly talking about the ability of embryonic stem cells, a noun, to do something. Hence, we must use the expression “ability to” to communicate that. Notice that use of “ability of developing” is not correct here because “developing” is an ‘ing” noun form, a gerund, and not a “proper” noun.

Hence, the context of the sentence determines the correct usage of the idiom appropriate for that particular sentence.