Which one of the following structures could be the effector in a reflex arc?

Here are the solutions to the questions:

6. Which one of the following structures could be the effector in a reflex arc?

An effector is a part of the body, typically a muscle or a gland, that responds to a stimulus after receiving a signal from the central nervous system.

• A salivary gland secretes saliva in response to stimuli (e.g., smell of food), making it an effector.
• A cone cell is a receptor, detecting light.
• The brain and spinal cord are parts of the central nervous system, involved in processing and transmitting signals, not directly carrying out the response.

The correct option is A.
$\boxed{\text{A. a salivary gland}}$

7. The following is a diagram of the human female reproductive system.
Which statement correctly describes the function of X?

Structure X in the diagram points to an ovary. The ovaries have two primary functions:

1. Production of gametes: They produce female gametes (ova or eggs) through a process called oogenesis.
2. Secretion of hormones: They secrete female sex hormones, primarily estrogen and progesterone, which are crucial for the menstrual cycle, pregnancy, and the development of female secondary sexual characteristics.

The correct option is A.
$\boxed{\text{A. hormone secretion and the production of gametes}}$

8. The table shows the menstrual cycle of a woman during the month of September.
Key:
[blank square] = menstruation
[shaded square] = ovulation (September 15th)

Why can fertilisation not take place if sperms are released into the vagina on the 8 September?

• Ovulation occurs on September 15th. An egg is typically viable for fertilization for about 12-24 hours after ovulation.
• Sperm survival: Sperm can survive in the female reproductive tract for approximately 3 to 5 days.
• If sperm are released on September 8th, and they can survive for a maximum of 5 days, they would be viable until September 13th (8 + 5 = 13).
• Since ovulation occurs on September 15th, the sperm released on September 8th would no longer be viable by the time the egg is released.

The correct option is B.
$\boxed{\text{B. Sperms can only survive in the female reproductive system for 3 or 4 days.}}$