Arthropods -

Options

A. Are mostly dioecious
B. Are mostly oviparous
C. Show usually internal fertilization and direct or indirect development
D. All

Answer

**Step-by-Step Solution:**

1. **Definition of Arthropods**: Arthropods are a diverse group of invertebrate animals that have an exoskeleton, segmented bodies, and jointed appendages. They include insects, arachnids, crustaceans, and more.

2. **Sexual Reproduction**: Arthropods are mostly dioecious, meaning that they have separate sexes. This means that male and female individuals are distinct and can be identified separately.

3. **Reproductive Method**: Most arthropods are oviparous, which means they reproduce by laying eggs. The eggs eventually hatch into new offspring.

4. **Fertilization Process**: The fertilization in arthropods is usually internal. This means that the male transfers sperm to the female inside her body, where fertilization occurs.

5. **Developmental Stages**: Arthropods can undergo either direct or indirect development.
- **Direct Development**: In this case, the young resemble the adults and there is no larval stage.
- **Indirect Development**: This involves multiple stages, including a larval stage, which undergoes metamorphosis to become an adult.

6. **Conclusion**: All the statements regarding arthropods being dioecious, oviparous, undergoing internal fertilization, and having direct or indirect development are correct. Therefore, the last option stating that all are correct is the right choice.