Living Environment - Part A

In an animal cell, all of the organelles work together to carry out

• photosynthesis

• diffusion

• metabolic processes

• information storage

A colony of 47,000 quaking aspen trees, all connected by one root system, is considered to be Earth’s most massive organism. When the trees are stressed, shoots are sent out from the roots and develop into new trees. Every new tree in this colony would contain

• the same genetic information, because it is produced asexually

• the same genetic information, because it is produced sexually

• less genetic material, since it is produced from root cells

• a different combination of genes, since it is produced from various roots

Scientists have found that different tissues in the prostate gland, a male reproductive organ, respond to different hormones. The tissues in the center area of the gland respond to testosterone and the tissues in the outer area of the gland respond to estrogen. The cells that make up these two regions of the prostate are different in that

• cells in the center area produce more estrogen than cells in the outer area

• cells in the outer area have many testosterone receptors

• they contain different receptors on their cell membranes

• they contain different DNA sequences for the production of hormones

Energy transfers in a natural ecosystem are represented in the diagram below. Which statement about this ecosystem is correct?

• A reduction in the number of species present would most likely upset the stability of this ecosystem.

• This ecosystem would not be affected if decomposers did not perform their function.

• This ecosystem lacks producer organisms.

• There are most likely more foxes than rabbits in this ecosystem.

The process of differentiation occurs when

• (1) two different cells, a sperm cell and an egg cell, combine to produce a zygote

• (2) different zygotes are formed each time that an egg and sperm unite

• (3) different kinds of cells and tissues form during embryonic development

• (4) two different sexes are present among the offspring, after sexual reproduction

Which two human systems work together to provide glucose for the cells of the body?

• nervous and reproductive systems

• nervous and respiratory systems

• circulatory and digestive systems

• circulatory and respiratory systems

The chart below includes structures found in a multicellular organism. Which row contains the structures that would be most numerous?

• organs

• tissues

• organelles

• cells

Dioxin, a toxin associated with waste incineration and some plastics, has been found to directly disrupt normal gamete production in human females. Dioxin most likely affects the

• testes and progesterone production

• ovaries and estrogen production

• DNA in the nuclei of sperm cells

• pancreas and insulin production

A gene present only in a single plant species was found to regulate protein content. This gene could increase the protein content of other food crops in the developing world. The most likely method that scientists would use to incorporate this gene into a variety of food crops is

• genetic engineering

• selective breeding

• sexual reproduction between the plants with this gene and those without it

• deletion of the genes that limit protein production from each individual food crop plant

A decrease in predators within an ecosystem would lead to an increase in herbivores. The increase in herbivores would cause a decrease in

• decomposers

• prey

• consumers

• producers