Science Form 3 Chapter 4 And 5 (Revision)

The correct answer is Sexual and Asexual. Reproduction can occur through sexual or asexual means. Sexual reproduction involves the fusion of gametes from two parents, resulting in offspring with a combination of genetic traits. Asexual reproduction, on the other hand, involves the production of offspring without the involvement of gametes or the fusion of genetic material.

Self-pollination refers to the transfer of pollen from the anther to the stigma of the same flower or within the same plant. Cross-pollination, on the other hand, involves the transfer of pollen from the anther of one flower to the stigma of another flower, often of a different plant. This can occur through various means such as wind, water, or pollinators like insects, birds, or bats. Both self-pollination and cross-pollination are important for plant reproduction and genetic diversity.

The scrotum is a pouch-like structure that holds and protects the testes. It helps to regulate the temperature of the testes, as sperm production requires a slightly lower temperature than the rest of the body. The scrotum contracts in cold temperatures to bring the testes closer to the body for warmth, and relaxes in warm temperatures to keep the testes cooler. Additionally, the scrotum acts as a protective layer for the testes, shielding them from potential injury.

The given correct answer is "Binary fusion, regeneration." Binary fusion is a form of asexual reproduction where two organisms combine their genetic material to form a new organism. Regeneration is the ability of an organism to regrow lost or damaged body parts. Both binary fusion and regeneration are types of asexual reproduction, where offspring are produced without the involvement of gametes or fertilization.

During adolescence, boys tend to experience a growth spurt, characterized by a rapid increase in height and weight. This is due to the surge in hormones, particularly testosterone, which leads to the development of secondary sexual characteristics and overall physical growth. Girls also experience growth during this time, but it generally occurs at a slower pace compared to boys. Therefore, the correct answer is "Rapid growth" as it accurately reflects the typical growth pattern seen in boys after the age of 14.

Growth refers to the process of increasing body size, number of cells, and weight. It is a natural and essential part of development in living organisms. As an organism grows, its body size increases, which is accompanied by an increase in the number of cells and overall weight. This growth is regulated by various factors such as genetics, nutrition, and hormones.

The correct answer is the premenstrual phase. This phase occurs in the menstrual cycle a few days before menstruation begins. During this phase, the levels of estrogen and progesterone decrease, causing physical and emotional symptoms such as bloating, mood swings, and breast tenderness. It is a preparatory phase for menstruation and is characterized by changes in the uterine lining in anticipation of shedding during the menstrual phase.