What is the main goal for gene therapy?

a. to cure human diseases .
b. to produce inexpensive medicine.
c. to lower the costs of livestock production.
d. to increase the nutritional value in foods.

Which statement describes compounds a. compounds are made of one type of atom. b. compounds cannot be represented by models. c. compounds are represented by chemical formulas. d. compounds cannot be broken down into simpler forms.

When an object is moving away from you while still making a sound, the pitch of the sound is perceived to a. lower b. unchanged c. fluctuating d.higher

How secretion and excretion both are different? explain in simple language.