Female Ascaris is differentiated from male by having
A. cloaca
B. penial setae
C. shorter size
D. straight posterior end

Hint: Ascaris lumbricoides and suum commonly called roundworms belong to the phylum Nematoda. They are the commonly occurring parasites found in the human body.

Complete answer:
Ascaris lumbricoides is a human parasite and causes ascariasis. The eggs of these worms are laid in soil and plants. When plants are consumed by humans, the parasite enters the body and affects the human intestine. It causes intestinal diseases. There are two kinds of ascaris: male and female. Both are slightly different in appearance. Let's analyze the options.

Option A: Cloaca is an opening for the reproductive,urinary and digestive tract. Females possess a vulva or genital pore whereas males do not have a separate genital pore. Therefore, this is an incorrect option.

Option B: Penial setae are two small sacs that open into cloaca. They have spicules in them which during mating helps to keep the female’s vulva open. Therefore, this is the incorrect option.

Option C: Males are generally 15-30 cm long and females are 20-35 cm long. Males are usually shorter than females. Therefore, this is the incorrect option.

Option D: Females have straight posterior ends while male have a hooked posterior end. Therefore, this is the incorrect option.

Hence, the correct answer is option (D).

Note: Ascaris are unisexual. They have a single-host life cycle and infection to the human host is majorly by consuming contaminated food and water.