Sexual reproduction

The governing concept is genetic variation in sexual reproduction. During this process, genetic material from two parents is combined, and the formation of gametes and their fusion create new combinations of genes. These combinations make offspring different from one another and from either parent, although inheritance still follows biological rules. Therefore option A is correct. The other options are false because sexual reproduction requires parents, does not produce identical offspring, and does not eliminate chromosomes.

The governing concept is genetic recombination in sexual reproduction. Each parent contributes a set of genes through a gamete, and fertilisation combines genetic material from two individuals. Meiosis and the random union of gametes create new combinations of alleles, so offspring are not genetically identical to either parent or usually to one another. Therefore option A is correct; the other statements describe or imply asexual reproduction incorrectly.

Sexual reproduction usually involves two parents and the formation of gametes through meiosis. Recombination, independent assortment, and the random fusion of male and female gametes create new combinations of alleles in offspring. Consequently, offspring often differ from one another and from their parents. Asexual reproduction generally uses one parent and produces genetically similar clones, apart from occasional mutations. Therefore option A is correct.

Sexual reproduction combines genetic material from two parents. Meiosis produces varied gametes, and fertilisation joins one gamete from each parent, creating a new genetic combination in the offspring. This makes variation generally greater than in asexual reproduction, where one parent produces a nearly similar copy. Hence option A is correct; options B, C, and D contradict the process.

Sexual reproduction combines genetic material from two parents. During meiosis, chromosomes and alleles are assorted and recombined, and fertilisation joins one gamete from each parent in a new combination. Consequently, offspring usually differ from both parents and from one another, providing variation on which selection can act. Option B correctly describes this process. A describes asexual reproduction, C is biologically false, and D is the opposite of the expected result.

In pollination, pollen grains are transferred from the anther to the stigma of a flower. Therefore, option A is correct. Fusion of male and female gametes is fertilisation, not pollination, and seed formation occurs after fertilisation. Exam tip: pollination means anther to stigma; fertilisation means fusion of gametes.

The sperm is the male gamete, or male reproductive cell, in humans. It carries genetic material from the father and fuses with the female gamete, the ovum, during fertilisation. This fusion produces a zygote, which later develops through successive stages into an embryo. Therefore, the ovum is the female gamete, while zygote and embryo are developmental stages or products after fertilisation. Option A is correct.

The ovum is the female gamete, or reproductive cell, in humans. It is produced in the ovaries and fuses with a sperm during fertilisation to form a zygote. A sperm is the male gamete, whereas a zygote is formed after fertilisation. Exam tip: Remember—ovum is the female gamete and sperm is the male gamete.